Liquid crystal display and manufacture thereof with electrostatic control of sprayed spacer particle deposition

ABSTRACT

This invention has its object to provide a method of liquid display device production which enables spacer disposition in interelectrode spaces not having electrode, namely at black matrix sites, in STN type and TFT type liquid crystal display devices and further enables even spacer disposition to attain a uniform cell thickness all over the substrate to thereby produce liquid crystal display devices of high contrast and high display uniformity stably and in good yields, with a reduced spray step tact time, as well as liquid crystal display devices produced by such method. 
     This invention provides a method for producing a liquid crystal display device 
     comprising spraying spacers onto at least one of a first substrate comprising at least pattern-forming transparent electrodes and a second substrate to be disposed opposingly above the first substrate and filling a liquid crystal into the space between both the substrates, 
     and comprising, in spraying positively or negatively charged spacers onto the substrate, disposing the substrate in close contact with an earthed conductive stage having a volume resistance of not more than 10 10  Ωcm and applying, to the transparent electrodes, a voltage of 200 V to 5 kV having the same polarity as the spacer charge polarity.

TECHNICAL FIELD

The present invention relates to a method for producing a liquid crystaldisplay device and to a liquid crystal display device.

BACKGROUND ART

Liquid crystal display devices are widely used in personal computers,portable electronic apparatus and the like. Generally, a liquid crystaldisplay device comprises, as shown in FIG. 36, a liquid crystal layer 7sandwiched between two substrates 1, on which color filters 4, a blackmatrix 5, transparent electrodes 3, an alignment layer 9 and so on areformed.

A TFT (thin film transistor) type liquid display device, as shown inFIG. 37, comprises a liquid crystal layer 7 sandwiched between asubstrate 1 a, which comprises a glass substrate 1 with transparentelectrodes 3, color filters 4, a conductive black matrix 5, an overcoatlayer 6, an alignment layer 9 and so on formed thereon, and a substrate1 b, which comprises a glass substrate 1 with transparent electrodes 3each comprising a source electrode 14 a, a drain electrode 14 and so on,insulating films 23, semiconductor films 16, gate electrodes 13, analignment layer 9 and so on formed thereon.

In these liquid crystal display devices, it is spacers that regulate thedistance between the two substrates and maintain the thickness of theliquid crystal layer at an appropriate level.

According to the prior art methods of liquid crystal display deviceproduction, spacers are sprayed and dispersed randomly but uniformlyover the substrate on which pixel electrodes are formed. Therefore, asshown in FIG. 36 and FIG. 37, spacers are disposed also at the sites ofsome pixel electrodes, namely at some display sites of the liquidcrystal display device. Spacers are generally made of a synthetic resin,glass or a like material and, when a spacer is disposed on a pixelelectrode, its depolarizing action causes light leakage at the spacersite. Further, the liquid crystal alignment is disturbed on the spacersurface, causing a bright defect, hence the contrast and color tone aredecreased and the display quality is deteriorated.

To solve such problems as mentioned above, spacers should be disposedonly in spaces among neighboring electrodes, which are not displaysites, namely only at sites covered by the black matrix, which is alight shield layer. The black matrix is provided for the purpose ofimproving the contrast of display of a liquid crystal display device or,in the case of a TFT type liquid crystal display device, for the purposeof preventing error operation of elements due to external light.

A technology of disposing spacers at sites corresponding to the blackmatrix, namely at sites other than display pixel sites, of a TFT typeliquid crystal display device is disclosed in Japanese Kokai PublicationHei-04-256925 which comprises maintaining the gate electrode and drainelectrode at the same electric potential in the step of sprayingspacers. Further, Japanese Kokai Publication Hei-05-53121 discloses amethod comprising applying a voltage to the circuit electrodes in thestep of spacer spraying, while Japanese Kokai Publication Hei-05-61052discloses a method comprising applying a positive voltage to the circuitelectrodes and charging spacers negatively and spraying them by the drymethod.

The inventions described in the references cited above use a substratehaving thin film transistors (TFTs) formed thereon and control thespacer disposition by applying a voltage to the circuits of these thinfilm transistors.

However, they have a problem. Namely, application of a voltage to thesubstrate having thin film transistors (TFTS) formed thereon, for thepurpose of controlling the spacer disposition may lead to destruction ofelements by that voltage, hence to failure to function as a liquidcrystal display device.

There is another problem. Namely, such technologies as mentioned abovecannot be employed in STN type liquid display devices since the sitescorresponding to the black matrix are spaces among transparentelectrodes.

On the other hand, as a technology of disposing spacers in spacesbetween stripe-form transparent electrodes constituted by disposing aplurality of linear transparent electrodes in parallel on a substrate,as in STN type liquid crystal display devices, there is disclosed, inJapanese Kokai Publication Hei-04-204417, a method of producing liquidcrystal display devices which comprises charging spacers eitherpositively or negatively and applying a voltage of the same polarity tothe linear transparent electrodes on the substrate in the step of spacerspraying.

This production method is intended to dispose spacers in interelectrodespaces by applying a voltage of the same polarity as the spacer chargepolarity to the linear transparent electrodes to thereby causespacer-electrode repulsion. However, mere application of a voltage ofthe same polarity as the spacer charge to the linear transparentelectrodes cannot attain a sufficient reduction in electric potentialbetween the transparent electrodes but leads to such a state as shown inFIG. 9. Thus, any electric field suited for spacer disposition is notformed, hence the precision of spacer disposition is very poor. It istherefore impossible to improve the contrast of the product liquidcrystal display device to a satisfactory extent.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amethod for producing a liquid display device by which the above problemsare solved and which enables spacer disposition in interelectrode spaceswhere there is no electrode, namely at black matrix sites, in STN typeand TFT type liquid crystal display devices and further enables evenspacer disposition to attain a uniform cell thickness all over thesubstrate to thereby produce liquid crystal display devices of highcontrast and high display uniformity stably and in good yields, with areduced spray step tact time, as well as liquid crystal display devicesproduced by such method.

In a first aspect, the present invention provides a method for producinga liquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes and a secondsubstrate to be disposed opposingly above the first substrate

and filling a liquid crystal into the space between both the substrates,

wherein, in spraying positively or negatively charged spacers onto thesubstrate, disposing the substrate in close contact with an earthedconductive stage having a volume resistance of not more than 10¹⁰ Ωcm,

and a voltage of 200 V to 5 kV having the same polarity as the spacercharge polarity is applied to the transparent electrodes.

In a second aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes, a conductiveblack matrix and an overcoat layer and a second substrate to be disposedopposingly above the first substrate

and filling a liquid crystal into the space between both the substrates,

wherein, in spraying positively or negatively charged spacers onto thesubstrate, a voltage (V1) is applied to the conductive black matrix anda voltage (V2) to the transparent electrodes,

both the voltages V1 and V2 being positive ones and satisfying therelation V1<V2 when the spacer charge polarity is positive,

or both V1 and V2 being negative voltages and satisfying the relationV1>V2 when the spacer charge polarity is negative.

In a third aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes, an alignmentlayer and one or more display areas and a second substrate to bedisposed opposingly above the first substrate

and filling a liquid crystal into the space between both the substrates,

wherein, in spraying positively or negatively charged spacers onto thesubstrate, the substrate is disposesd in close contact with an earthedconductive stage having a size smaller than the substrate size tothereby allow the peripheral edge portions thereof to be apart from theconductive stage,

and a voltage of the same polarity as the spacer charge polarity isapplied to the transparent electrodes on the substrate.

In a fourth aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes and analignment layer and a second substrate to be disposed opposingly abovethe first substrate

and filling a liquid crystal into the space between both the substrates,

and comprising the step of removing water from the substrate onto whichspacers are to be sprayed, and the step of bringing the substrate intoclose contact with an earthed conductive stage and then spraying spacerswhile applying a voltage of the same polarity as the spacer chargepolarity to the transparent electrodes on the substrate.

In a fifth aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes and analignment layer and a second substrate to be disposed opposingly abovethe first substrate

and filling a liquid crystal into the space between both the substrates,

and comprising the step of disposing the substrate into close contactwith an earthed conductive stage and spraying spacers while applying avoltage of the same polarity as the spacer charge polarity to thetransparent electrodes on the substrate,

the substrate before and during spacer spraying showing characteristicssuch that, when a voltage of 1 kV is applied to the transparentelectrodes on the substrate, the current flowing between the transparentelectrodes on the substrate and the conductive stage is not more than10⁻⁶ A.

In a sixth aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrodes and analignment layer and a second substrate to be disposed opposingly abovethe first substrate

and filling a liquid crystal into the space between both the substrates,

wherein, in spraying positively or negatively charged spacers onto thesubstrate, the substrate is disposed into close contact with an earthedconductive stage,

a voltage of the same polarity as the spacer charge polarity is appliedto the transparent electrodes on the substrate,

then the terminals of the voltage application apparatus are disconnectedfrom the transparent electrodes,

and spacer spraying is carried out while the electric charge remains onthe substrate.

In a seventh aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto at least one of a first substratecomprising at least pattern-forming transparent electrode and analignment layer and a second substrate to be disposed opposingly abovethe first substrate

and filling a liquid crystal into the space between both the substrates,

wherein, in spraying positively or negatively charged spacers onto thesubstrate, the substrate is disposed into close contact with an earthedconductive stage,

a voltage of the same polarity as the spacer charge polarity is appliedto the transparent electrodes on the substrate while maintaining thatstate of voltage application for a certain period of time

and then spacer spraying is carried out while maintaining that state ofvoltage application.

In an eighth aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto a first substrate comprising at leastpattern-forming transparent electrode, a conductive black matrix, anovercoat layer and an alignment layer,

and filling a liquid crystal into the space between the first substrateand a second substrate comprising thin film transistors formed thereonwhich is to be disposed opposingly above the first substrate,

wherein the first substrate has transparent electrode-free etchedregions formed within the transparent electrodes over and within theexpanse of the corresponding conductive black matrix areas,

and, in spraying positively or negatively charged spacers onto the firstsubstrate, a voltage (V1) is applied to the conductive black matrix anda voltage (V2) to the transparent electrodes,

both the voltages V1 and V2 being positive ones and satisfying therelation V1<V2, when the spacer charge polarity is positive,

or both V1 and V2 being negative voltages and satisfying the relationV1>V2, when the spacer charge polarity is negative.

In a ninth aspect, the invention provides a method for producing aliquid crystal display device

comprising spraying spacers onto a first substrate comprising at leastpattern-forming transparent electrodes, a black matrix, an overcoatlayer and an alignment layer,

and filling a liquid crystal into the space between the first substrateand a second substrate comprising thin film transistors formed thereonwhich is to be disposed opposingly above the first substrate,

wherein the first substrate has transparent electrode-free etchedregions formed within the transparent electrodes over and within theexpanse of the corresponding conductive black matrix areas,

and, in spraying positively or negatively charged spacers onto the firstsubstrate, the first substrate is disposed into close contact with anearthed conductive stage having a volume resistance of not more than10¹⁰ Ωcm

and a voltage of 200 V to 5 kV having the same polarity as the spacercharge polarity is applied to the transparent electrodes.

In a tenth aspect, the invention provides a method for producing aliquid crystal display device comprising spraying spacers onto a firstsubstrate comprising at least pattern-forming transparent electrodes,

and filling a liquid crystal into the space between the first substrateand a second substrate comprising thin film transistors formed thereonwhich is to be disposed opposingly above the first substrate,

wherein the first substrate has isolated, electrically floating,transparent electrodes not connected with the surrounding transparentelectrodes but formed within the transparent electrodes within theexpanse of the corresponding black matrix areas as formed on the firstor second substrate,

and, in spraying positively or negatively charged spacers onto the firstsubstrate, the first substrate is disposed in close contact with anearthed conductive stage having a volume resistance of not more than10¹⁰ Ωcm

and a voltage of the same polarity as the spacer charge polarity isapplied to the transparent electrodes other than the isolatedtransparent electrodes on the first substrate.

In an eleventh aspect, the invention provides a method for producing aliquid crystal display device according to the first, second, third,fourth, fifth, sixth, seventh, eighth, ninth or tenth aspect of theinvention,

wherein spacers are charged positively or negatively by being sprayedthrough a pipeline made of a resin or a metal using a gas as a medium.

In a twelfth aspect, the invention provides a method for producing aliquid crystal display device according to the first, second, third,fourth, fifth, sixth, seventh, eighth, ninth, tenth or eleventh aspectof the invention,

wherein spacers are fixed on the substrate surface by heating.

In a thirteenth aspect, the invention provides liquid crystal displaydevices produced by the method for producing a liquid crystal displaydevice according to the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, eleventh or twelfth aspect of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view illustrating an equipotentialsurface on the substrate when the stage is earthed.

FIG. 2 is schematic view illustrating the method for producing a liquidcrystal display device according to an aspect of the present invention.

FIG. 3 is a schematic plan view, seen from above, of a substrate to beused in the liquid crystal display device production method according toan aspect of the invention on which substrate no dummy electrode isformed.

FIG. 4 is a schematic plan view, seen from above, of a substrate to beused in the liquid crystal display device production method according toan aspect of the invention on which substrate a dummy electrode isformed and the transparent electrodes are not connected with the dummyelectrode.

FIG. 5 is a schematic plan view, seen from above, of a substrate to beused in the liquid crystal display device production method according toan aspect of the invention on which substrate a dummy electrode isformed and the transparent electrodes are connected with the dummyelectrode.

FIG. 6 is a schematic view illustrating lines of electric force as seenwith a substrate having transparent electrodes alone formed on anovercoat layer when different voltages of the same polarity arerespectively applied to the transparent electrodes and the black matrix.

FIG. 7 is a schematic view illustrating lines of electric force as seenwith a substrate having transparent electrodes and a dummy electrodeformed on an overcoat layer when different voltages of the same polarityare respectively applied to the transparent and dummy electrodes and theblack matrix.

FIG. 8 is a schematic sectional view illustrating an equipotentialsurface on the substrate in the conventional method for producing aliquid crystal display device.

FIG. 9 is a schematic sectional view illustrating an equipotentialsurface on the substrate when the stage is not earthed.

FIG. 10 is a schematic sectional view illustrating a relationshipbetween the substrate and the stage in the method for producing a liquidcrystal display device.

FIG. 11 is a schematic sectional view illustrating a relationshipbetween the substrate and the stage in the method for producing a liquidcrystal display device.

FIG. 12 is a schematic view, on a horizontal plane and in section,illustrating the picture frame-like state of the black matrix on anordinary common electrode substrate in the method for producing a liquidcrystal display device according to an aspect of the present invention.

FIG. 13 is a schematic sectional view illustrating an equipotentialsurface on the substrate in the method for producing a liquid crystaldisplay device according to an aspect of the present invention.

FIG. 14 is a schematic side view illustrating the case of currentleakage through moisture on the substrate surface to the stage side.

FIG. 15 is a schematic side view illustrating an equipotential surfaceon the substrate when the stage is earthed.

FIG. 16 is a schematic side view illustrating an equipotential surfaceon the substrate when the substrate surface is covered with moisture.

FIG. 17 is a schematic side view illustrating a leakage currentdetecting system which has an electrometer disposed between thetransparent electrodes and the conductive stage and is to be used in themethod for producing a liquid crystal display device according to anaspect of the present invention.

FIG. 18 is a schematic side view illustrating how an electric fieldsuited for spacer spraying is maintained by disposing a substrate inclose contact with an earthed conductive stage (table), applying avoltage of the same polarity as the spacer charge polarity to thepattern-forming transparent electrodes formed on the substrate ontowhich spacers are to be sprayed, and then removing, from the transparentelectrodes, the terminals from the voltage application apparatus whileapplying the voltage of the same polarity as the spacer charge polarityto the pattern-forming transparent electrodes.

FIG. 19 is a schematic side view illustrating how the step of voltageapplication within a spray apparatus can be omitted and the tact timereduced by applying a voltage to the transparent electrodes on anearthed conductive stage prior to the step of spacer spraying andcausing them to pass through the spray apparatus together with theconductive stage (table)

FIG. 20 is a schematic plan view illustrating an embodiment of the firstsubstrate of the present invention, with etched areas formed thereon.

FIG. 21 is a schematic plan view illustrating another embodiment of thefirst substrate of the present invention, with etched areas formedthereon.

FIG. 22 is a schematic plan view illustrating a further embodiment ofthe first substrate of the present invention, with etched areas formedthereon.

FIG. 23 is a schematic plan view illustrating a still further embodimentof-the first substrate of the present invention, with etched areasformed thereon.

FIG. 24 is a schematic sectional view illustrating the method forproducing a liquid crystal display device according to an aspect of thepresent invention.

FIG. 25 is a schematic plan view illustrating an embodiment of the firstsubstrate of the present invention, with isolated transparent electrodesformed thereon.

FIG. 26 is a schematic plan view illustrating another embodiment of thefirst substrate of the present invention, with isolated transparentelectrodes formed thereon.

FIG. 27 is a schematic plan view illustrating a further embodiment ofthe first substrate of the present invention, with isolated transparentelectrodes formed thereon.

FIG. 28 is a schematic plan view illustrating a still further embodimentof the first substrate of the present invention, with isolatedtransparent electrodes formed thereon.

FIG. 29 is a schematic sectional view of a spacer sprayer to be used inthe practice of the method for producing a liquid crystal display deviceaccording to an aspect of the present invention.

FIG. 30 is a schematic sectional view of a spacer sprayer to be used inthe practice of the method for producing a liquid crystal display deviceaccording to an aspect of the present invention.

FIG. 31 is a schematic sectional view of a spacer sprayer to be used inthe practice of the method for producing a liquid crystal display deviceaccording to an aspect of the present invention.

FIG. 32 is a schematic sectional view of a spacer sprayer to be used inthe practice of the method for producing a liquid crystal display deviceaccording to an aspect of the present invention.

FIG. 33 is a plan view illustrating the state after spacer spraying ontothe substrate shown in FIG. 23.

FIG. 34 is a schematic sectional view of a spacer sprayer to be used inthe practice of the method for producing a liquid crystal display deviceaccording to an aspect of the present invention.

FIG. 35 is a plan view illustrating the state after spacer spraying ontothe substrate shown in FIG. 28.

FIG. 36 is a schematic view illustrating the conventional method forproducing a liquid crystal display device.

FIG. 37 is a schematic view illustrating the conventional method ofTFT-type liquid crystal display device production.

EXPLANATION OF CODES

1—insulating substrate (glass substrate)

1 a—first substrate

1 b—second substrate

2—polarizer

3—display electrode (linear transparent electrode, pixel electrode)

3 a—isolated transparent electrode

4—color filter

5—black matrix (conductive black matrix)

6—overcoat layer

7—liquid crystal

8—spacer

9—alignment layer

10—chamber

12—voltage application apparatus (direct current source)

13—gate electrode

14—drain electrode

14 a—source electrode

15—conductive stage (stage)

16—semiconductor layer

17—pipeline

18—electrometer

19—spacer metering (dosing) feeder

20—parting line

21—dummy electrode

22—etched region

23—insulation layer

24—etched area

26—black matrix picture frame

28—dummy electrode region

29—display pixel (black matrix opening)

30—display area

31—equipotential line (equipotential surface)

DISCLOSURE OF THE INVENTION

In the following, the present invention is described in detail.

The method of liquid crystal display device (hereinafter referred toalso as LCD for short) production according to the first aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes and a second substrate to be disposed opposingly above thefirst substrate and filling a liquid crystal into the space between boththe substrates comprises, in spraying positively or negatively chargedspacers onto the substrate, disposing the substrate in close contactwith an earthed conductive stage having a volume resistance of not morethan 10¹⁰ Ωcm and applying, to the transparent electrodes, a voltage of200 V to 5 kV having the same polarity as the spacer charge polarity.

The method of LCD production according to the first aspect of theinvention is applied to the production of LCDs by spraying spacers ontoat least one of a first substrate comprising at least pattern-formingtransparent electrodes and a second substrate to be disposed opposinglyabove the first substrate and filling a liquid crystal into the spacebetween both the substrates.

The above transparent electrodes are not particularly restricted but maybe, for example, linearized transparent electrodes. The abovepattern-forming transparent electrodes are not particularly restrictedbut may be, for example, stripe-shaped electrodes constituted of lineartransparent electrodes disposed in parallel as formed on a substrate.The stripe-shaped electrodes are those used as the so-called displayelectrodes in liquid crystal display devices. The areas for displayingin a liquid crystal display device are display areas and each comprisesthe transparent electrode-forming area and the vicinity thereof.

The substrate to which the method of LCD production according to thefirst aspect of the present invention can be applied may be any onehaving at least pattern-forming transparent electrodes formed thereon,without any particular restriction as to the shape thereof, whethersubstrate-like or film-like, for instance. Thus, there may be mentioned,among others, color filter substrates having a black matrix, colorfilters, an overcoat layer, pattern-forming transparent electrodes andan alignment layer, and substrates having a black matrix, an overcoatlayer, pattern-forming transparent electrodes and an alignment layer.When a metal substrate is used, however, it is necessary to provide aninsulation layer so that the electrodes formed on the surface may not beshort-circuited.

Thus, when the method of LCD production according to the first aspect ofthe invention is applied to the production of STN type LCDs, the methodcan be applied to either common electrode substrates or segmentelectrode substrates facing thereto on condition that they havepattern-forming transparent electrodes at a minimum.

The spacers mentioned above are not particularly restricted but include,among others, metal particles; synthetic resin particles; inorganicparticles; opaque synthetic resin particles containing a pigmentdispersed therein; dye-colored particles; particles showing adhesivenessupon heating or light irradiation; and metal, synthetic resin orinorganic particles the surface of which is metal-plated. The spacersserve to adjust the cell thickness in liquid crystal display devices.

In applying the method of LCD production according to the first aspectof the invention to the production of TFT type LCDs, transparentelectrode-free areas are formed, by etching, for instance, at sites justbelow the black matrix sites of the color filter substrate, which is acommon-electrode substrate, and spacers are then disposed on thesubstrate having such areas by the method of LCD production according tothe first aspect of the invention. While the common electrode substratein ordinary TFT type liquid crystal display devices comprises a solidelectrode, it is possible to drive even an electrode substratecomprising etched transparent electrodes in the same manner as inordinary TFT type liquid crystal display devices by applying the samevoltage to the respective electrodes.

The method of LCD production according to the first aspect of theinvention is carried out by disposing, in spraying positively ornegatively charged spacers onto a substrate, the substrate in closecontact with an earthed conductive stage (referred to also as stage forshort) having a volume resistance of not more than 10¹⁰ Ωcm and applyinga voltage of 200 V to 5 kV having the same polarity as the spacer chargepolarity to the transparent electrodes.

By disposing the substrate in close contact with the earthed conductivestage having a volume resistance of not more than 10₁₀ Ωcm, the electricpotential in each gap between the transparent electrodes is reduced andan electric field suited for spacer disposition is formed, as shown inFIG. 1.

It is necessary that the volume resistance of the above conductive stagebe not more than 10¹⁰ Ωcm. The substrate is may be in close contact withthe conductive stage only over a certain area thereof.

The value of the voltage to be applied to the above transparentelectrodes is 200 V to 5 kV. This value generally makes it possible toproduce a sufficient.repulsive force against the spacer charge. Thus,precise spacer positioning can be attained. A preferred voltage is 1.5kV to 5 kV. The kind of voltage is not particularly restricted. A directcurrent voltage or a pulse voltage, for instance, is suited for use.

The method of spacer spraying may be either the dry method or wetmethod. In view of possible leak between transparent electrodes underthe influence of moisture, the dry method of spraying is preferred,however.

As the method of charging or electrifying spacers in the above-mentioneddry method of spraying, there may be mentioned, for example, thecharging method which comprises causing spacers to contact with thepipeline wall repeatedly. In this charging method, stable charging canbe attained by passing spacers through the pipeline by means of such amedium as compressed air or compressed nitrogen. In that case, from theviewpoint of spacer charging and of prevention of moisture adhesion tothe substrate surface, the medium gas should preferably be in a drystate or as low as possible in moisture content.

The above pipeline may be made of a metal or a resin and it can properlybe selected in correlation with the spacer charge polarity and thequantity of electric charge.

The metal pipeline is not particularly restricted but includes, amongothers, pipelines made of a single material, such as nickel, copper,aluminum or titanium; and pipelines made of an alloy, such as stainlesssteel. The pipeline inside wall may have a coat of a metal, such as goldor chromium, provided by plating, for instance.

The resin pipeline is not particularly restricted but includes, amongothers, pipelines made of Teflon, polyvinyl chloride, nylon or the like.When a pipeline made of a highly insulating resin, such as Teflon, isused, it is preferred that such a resin pipeline be coated with a metalor a metal wire or line be inserted in the pipeline, with the metal coator metal wire or line being earthed. This is because while charge goingin and charge going out are effected by contacting of spacers with thepipeline, the charge on the resin pipeline accumulates, leading tofailure to attain stable charging, if the pipeline is not earthed.

For adjusting the quantity of charge on spacers, pipelines differing inmaterial of construction may be connected up in series.

The method of LCD production according to the second aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes, a conductive black matrix and an overcoat layer and a secondsubstrate to be disposed opposingly above the first substrate andfilling a liquid crystal into the space between both the substratescomprises, in spraying positively or negatively charged spacers onto thesubstrate, applying a voltage (V1) to the conductive black matrix and avoltage (V2) to the transparent electrodes, both the voltages V1 and V2being positive ones and satisfying the relation v1<V2 when the spacercharge polarity is positive, or both V1 and V2 being negative voltagesand satisfying the relation V1>V2 when the spacer charge polarity isnegative.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe second aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

The above conductive black matrix (also referred to as black matrix)offers display areas in the manner of picture frames. The picture framecondition is formed by each area where there is no conductive blackmatrix.

The above conductive black matrix may be any conductive one, without anyparticular restriction. Thus, it includes, for example, those made ofchromium, aluminum or carbon black. From the viewpoint of conductivity,however, those made of a metal, preferably chromium, are used moreoften. As shown in FIG. 2, an insulating overcoat layer is provided onthe conductive black matrix. The overcoat layer is provided to prevent ashort circuit between the linear transparent electrodes and theconductive black matrix and it is not particularly restricted providedthat it is transparent and has an insulating power. It is made of anacrylic resin, for instance.

When the substrate is a substrate having color filters, the aboveovercoat layer also serves to level the color filter layer. Generally,such color filters can be formed by the pigment dispersing method ordyeing method, for instance.

By applying a voltage (V1) to the above conductive black matrix and avoltage (V2) to the transparent electrodes, an electric field suited forspacer positioning is formed, as shown in FIG. 2, in the same manner asshown in FIG. 1, irrespective of whether the substrate is disposed inclose contact with an earthed conductive stage having a volumeresistance of not more than 10¹⁰ Ωcm or not.

When the spacer charge is positive, for instance, positive voltages areselected as both the voltages and the condition V1<V2 is satisfied,whereby a strong repulsive force is produced on the transparentelectrodes and a weak repulsive force at sites of the black matrix andspacers can be disposed at those sites of the black matrix (thesituation is the same when the spacer charge is negative).

The reason why the above V1 and V2 should be of the same polarity as thespacer charge polarity is that a repulsive force of the order of kV isrequired for controlling the positions of fall of spacers with a highlevel of precision. If V1 and V2 differ in polarity, the potentialdifference between the transparent electrodes and the black matrix willbecome of the order of kV and a short circuit will be formed between thetransparent electrodes and the black matrix, since the overcoat layer isas thin as 2 to 5 μm; the result will be failure in forming an electricfield suited for spacer positioning.

Therefore, the potential difference between V1 and V2 is preferably notmore than 100 V. Even though the potential difference is as small as 100V or less, it is a potential difference in the repulsive phase, hencethe intended spacer positioning control can be accomplished.

Thus, when the polarity of the charge of spacers to be sprayed ispositive (+), the voltage (V1) applied to the conductive black matrixand the voltage (V2) applied to the transparent electrodes are selectedso that the relation V1<V2 may be satisfied.

By doing so, the repulsive force appearing at the black matrix sitesbecomes relatively smaller than the repulsive force appearing at thetransparent electrode sites, and the spacers are disposed at the blackmatrix sites, namely in each gap between the neighboring,pattern-forming transparent electrodes.

When the polarity of the charge of spacers to be sprayed is negative(−), the voltage (V1) applied to the conductive black matrix and thevoltage (V2) applied to the transparent electrodes are selected so thatthe relation V1>V2 may be satisfied.

The above V1 and V2 are both positive when the polarity of the charge ofspacers to be sprayed is positive (+) and, when the polarity of thecharge of spacers to be sprayed is negative (−), they are both negative.Thus, the potential difference between V1 and V2 is produced by usingthe same polarity as the spacer charge polarity, not by using theopposite polarity relative to the spacer charge polarity or using thepositive (+) polarity and negative (−) polarity relative to the earthpotential.

The reason why the potential difference between V1 and V2 is producedusing the same polarity as the spacer charge polarity is as follows.

When the above potential difference between V1 and V2 is produced usingthe opposite polarity relative to the spacer charge polarity or usingthe positive (+) polarity and negative (−) polarity relative to theearth potential, spacers first undergo the influence of gravity, hencetheir speed of falling tends to increase.

On the contrary, when the potential difference between V1 and V2 isproduced using the same polarity as the spacer charge polarity, thespeed of spacer falling tends to be suppressed under the influence ofthe resulting repulsive force. When the potential difference between V1and V2 remains the same, a slower falling speed makes it possible toachieve more precise spacer positioning.

More specifically, when, for instance, the spacer charge polarity isnegative (−) and a potential difference of 50 V is to be given betweenV1 and V2, the potential difference of 50 V is made not between +25 Vand −25V but between −1000 V and −1050 V, which are of the same polarityas the spacer charge polarity. In the initial stage of falling, namelywhen they are far from the substrate, spacers undergo only the influenceof an average electric field El resulting from the voltages −1000 V and−1050 V, since, in that stage, there is no substantial influence of thepotential difference as yet. Therefore, spacers with a charge quantity Qundergo only the influence of the attractive or repulsive force in thedirection of falling (vertical direction) as resulting from the electricfield El (F1=QE1). Then, as the spacers approach the substrate, theroute of spacer falling is bent (F2=QE2) by the influence of thepotential difference E2 (50 V) between −1000 V and −1050 V.

Therefore, the speed of spacers falling into the potential difference E2can be varied by selecting the voltage values for producing thepotential difference between V1 and V2. Thus, by adjusting the voltagevalues V1 and V2 and the potential difference therebetween, it ispossible to control the spacer positioning even with a small potentialdifference. The gist of the second aspect of the present invention liestherein. Namely, high precision spacer positioning can be attained bypositively adjusting the spacer falling speed by forming, on thesubstrate, an electric repulsive force field of the same polarity as thespacer charge polarity, not based only on the idea of polarity dueattractive force/repulsive force as in the prior art.

The potential difference between the above V1 and V2 is preferably notmore than 100 V. As mentioned above, the electric potentials V1 and V2are of the same polarity as the spacer charge polarity and, therefore,even when the potential difference is as small as 100 V or less, thespacer positioning control can be accomplished. Since the overcoat layeris as thin as 2 to 5 μm, breakdown tends to occur and the yield maybecome reduced when the potential difference is in excess of 100 V.

The quantity of spacer charge is preferably 3 to 50 μC/g, the polaritybeing either positive (+) or negative (−). This spacer charge quantityrange does not mean a dispersion in spacer charge quantity but meansthat the average spacer charge quantity is within the above range. Whenit is less than 3 μC/g, spacers may fail to make a sufficient bend,hence a high level of positioning may not be obtained in some instances.If, conversely, it is in excess of 50 μC/g, the repulsive force in anelectric field for repulsive force exertion will become too strong for asufficient number of spacers to fall on the substrate, hence a prolongedperiod of time will be required for spacer spraying; the positioningprecision also tends to become worse since the spacers show a certainextent of dispersion in spacer charge quantity.

The spacer charge quantity can be, measured using a model E-SPARTanalyzer (product of Hosokawa Micron), for instance.

In the above first and second aspects of the present invention, thesubstrate preferably has a dummy electrode.

FIGS. 3 to 5 each is a plan view showing a substrate of such type thattwo display substrates are produced from one substrate. The substrateshown in FIG. 4 or FIG. 5 is of the type such that a dummy electrode isprovided so as to surround each display area. Generally, this dummyelectrode is formed for preventing the alignment layer from beingdamaged by sparking due to static electricity in the production step.

In FIG. 3, there is no dummy electrode. In FIG. 4, there is a dummyelectrode but the transparent electrodes are not connected with thedummy electrode. In FIG. 5, there is a dummy electrode formed and thisis connected with the transparent electrodes.

Substrates having a dummy electrode in such a manner (FIG. 4 or FIG. 5)are used so that the number of spacers in the outermost region of eachdisplay area may be prevented from decreasing to thereby attain auniform overall cell gap.

When there is no dummy gap formed, the number of spacers in theoutermost region of the display area may easily be reduced for thefollowing reason. In the central portion of the display area in whichthe transparent electrodes are formed, the repulsive force-inducingelectric field is uniform, as shown in FIG. 6, and, therefore, thenumber of spacers disposed between each two transparent electrodes isstabilized. On the periphery (outside) of the display area, however, norepulsive force exists, so that spacers occurring in the vicinitythereof may readily be repelled out of the display area; as a result,the number of spacers in the outermost region tends to decrease.

In the central portion of the display area as well, the number ofpositioned spacers becomes smaller due to a repulsive force as comparedwith the case of no voltage application and, in particular, particleswith a large charge quantity are repelled out of the substrate.

However, when a voltage similar to that applied to the transparentelectrodes within the display area is applied to a dummy electrodedisposed outside the display area, the same electric field as over thedisplay area extends to the dummy electrode region, as shown in FIG. 7,and, accordingly, the number of spacers within the dummy electroderegion will not decrease appreciably but spacers are disposed uniformlywithin the whole display area. As a result, when a liquid crystaldisplay device is fabricated using such substrate, the cell gap becomesuniform throughout the display area, so that high display uniformity isinsured and high-contrast display is realized. In FIG. 6 and FIG. 7, theunderlying overcoat layer, black matrix layer and so forth are omitted.

When the transparent electrodes are connected with the dummy electrode,the same voltage is applied to the transparent electrodes, so thatuniform spacer disposition becomes possible, as mentioned above.

When the transparent electrodes are not connected with the dummyelectrode, it is preferred that a voltage different from that applied tothe transparent electrodes be applied to the dummy electrode.

The reason is as follows. When the display area is apart from the dummyelectrode, for instance, spacers may escape into gaps therebetween.Therefore, in such a case, it becomes necessary to apply, to the dummyelectrode, a stronger repulsive force causing voltage than that appliedto the display area to thereby drive back spacers, by repulsion, to theoutermost region of the display area.

The mode of connection of the transparent electrodes with the dummyelectrode includes, but is not limited to, the mode in which one end ofeach transparent electrode is connected with the dummy electrode, themode in which both ends of each transparent electrode are connected withthe dummy electrode, and the mode in which the aligned transparentelectrodes are connected alternately at one end and at the other withthe dummy electrode, for instance. To sum up, the respective transparentelectrodes may be connected in every possible manner with the dummyelectrode.

The method of LCD production according to the third aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes, an alignment layer and one or more display areas and asecond substrate to be disposed opposingly above the first substrate andfilling a liquid crystal into the space between both the substratescomprises disposing, in spraying positively or negatively chargedspacers onto the substrate, the substrate in close contact with anearthed conductive stage having a size smaller than the substrate sizeto thereby allow the peripheral edge portions thereof to be apart fromthe conductive stage, and applying a voltage of the same polarity as thespacer charge polarity to the transparent electrodes on the substrate.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe third aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

When, in spraying spacers, merely the charged spacers are of the samepolarity as that of the voltage-applied transparent electrodes, forexample when the spacer charge polarity is positive (+) and the voltageapplied to the transparent electrodes is of positive polarity (+), asshown in FIG. 8 (the color filters, overcoat and so forth not shown),the total number of spacers dispersed on the substrate becomes smallerand stabilized as compared with the case of no voltage application tothe transparent electrodes.

However, in the edge portions of the substrate where there is notransparent electrode, no repulsive force operates, so that spacersoccurring in the vicinity of the periphery of the substrate are repelledout of the substrate. Therefore, the number of spacers occurring in thevicinity of the periphery of the display area becomes insufficient, sothat the liquid display device may have a reduced cell thickness on thatperiphery, causing display unevenness.

In the production of STN type LCDs, for instance, when, in sprayingcharged spacers, the substrate comprising at least pattern-formingtransparent electrodes and an alignment layer and having a display areaor areas is not earthed or such substrate is disposed in close contactwith an unearthed conductive stage, as shown in FIG. 9, the electricpotential between the electrodes as resulting from application of avoltage of the same polarity as the charged spacers' polarity to thepattern-forming transparent electrodes will not lower but the electricfield formed over the substrate is nearly uniform (shown in FIG. 9 as anequipotential surface for a certain electric potential), hence asufficient electric potential distribution cannot be obtained and noselective spacer disposition is effected.

On the other hand, in spraying charged spacers, it is id possible todispose the spacers in gaps between the transparent electrodes by meansof a repulsive force by disposing a substrate comprising at leastpattern-forming transparent electrodes and an alignment layer in closecontact with an earthed conductive stage and applying a voltage of thesame polarity as the charged spacers' polarity to the transparentelectrodes on the substrate. In this case, the disposition of thesubstrate in close contact with the earthed conductive stage leads toformation of an electric field suited for spacer disposition.

In other words, when a + voltage is applied to the transparentelectrodes, the electric potential in the gap between each neighboringtransparent electrodes becomes sufficiently lower than the electricpotential of the transparent electrodes, since the stage, which isearthed, always maintains a zero electric potential. An electric fieldsuited for spacer disposition (in FIG. 1, shown as an equipotentialsurface for a certain electric potential) is thus formed. Namely,electric force lines, though not shown in FIG. 9 and FIG. 1, are formedin the gap between each transparent electrode and the neighboring oneand charged spacers are disposed in each gap between the transparentelectrodes under the action of the electric force lines and of therepulsive force from the substrate as a whole upon the charged spacerswith the same polarity as the voltage applied to the transparentelectrodes (the alignment layer and so forth not shown).

The above-mentioned stage is required to have a volume resistance of notmore than 10¹⁰ Ωcm and the above-mentioned substrate may be in closecontact with the stage over a certain percentage of the area of thesubstrate.

Meanwhile, a phenomenon was observed which consisted in the decrease innumber of spacers in the vicinity of the periphery of the display areaupon exertion of a repulsive force on the spacers as a result offormation of an electric field by a voltage applied to thepattern-forming transparent electrodes.

In the production of liquid crystal display devices, they experience astep of applying a certain load thereto. If, in that step, the number ofspacers becomes irregular or uneven in some part of the substrate, theload per spacer varies in that part to cause varying distortion ofspacers, leading to cell thickness variations and to uneven display bythe liquid crystal display device obtained.

The cause of such variation in the number of spacers in the vicinity ofthe periphery of the display area is that when a voltage of the samepolarity as the spacer charge polarity is applied to the pattern-formingtransparent electrodes to dispose spacers in the gaps among them, aforce (repulsive force) acts so as to repel the spacers falling over thedisplay area out of the display area. In the vicinity of the peripheryof the display area, in particular, as shown in FIGS. 1, 8 and 9, thosespacers which are to be disposed in the peripheral regions of thedisplay area escape to the outside, since no replusive force occurs onthat substrate region which is outside the display area.

Thus, as shown in FIG. 10, a repulsive force acts on spacers over thedisplay area since a voltage of the same polarity as the spacer chargepolarity is applied on the transparent electrodes within the substrate,while the conductive stage, which is at an earth potential, exerts anattractive force on charged spacers. Therefore, a repulsive force fromwithin the substrate and an attractive force from the conductive stageact on the periphery of the substrate and both the effects cause spacersto escape from within the substrate.

In accordance with the third aspect of the present invention, thesephenomena are prevented, as shown in FIG. 11, by disposing, in sprayingpositively or negatively charged spacers onto the substrate, thesubstrate in close contact with an earthed conductive stage having asize smaller than the substrate size to thereby allow the peripheraledge portions thereof to be apart from the conductive stage, andapplying a voltage of the same polarity as the spacer charge polarity tothe transparent electrodes on the substrate, whereby the effect ofearthing on the edge portions of the substrate as resulting from theconductive stage is weakened and spacers rather tend to be attracted bythe electric potential of the transparent electrodes. Thus, the decreasein the number of spacers disposed on the periphery of the substrate canbe prevented as compared with the case of the conductive stage having asize larger than the substrate size.

The earthed conductive stage preferably has a volume resistance value ofnot more than 1×10¹⁰ Ωcm. When it is in excess of 1×10¹⁰ Ωcm, the wholesubstrate acquires an electric potential close to that of thetransparent electrodes, so that the spacer positioning accuracy becomespoor.

The state that the peripheral edge portions of the substrate is apartfrom the conductive stage is a state such that the substrate isextending beyond the conductive stage, as shown in FIG. 11.

If there is an electrically isolated electrode, spacers will bedispersed in that portion concentratedly. Therefore, when a voltage ofthe same polarity as the spacer charge polarity is applied to thetransparent electrodes formed on the substrate, the voltage ispreferably applied to all the transparent electrodes so that noelectrically isolated electrode may occur.

The voltage to be applied to the transparent electrodes on the substrateis preferably several hundred volts to several thousand volts. When thevoltage applied is excessively low, it becomes difficult to control theroute of falling of spacers. When it is excessively high and when ablack matrix is employed, short circuiting may occur between thetransparent electrodes and the black matrix in some instances.

The substrate onto which spacers are to be sprayed may be one having ablack matrix formed thereon, and the black matrix may be an insulatingone or a conductive one. In any case, the same good effects as mentionedabove can be obtained.

The above black matrix is not particularly restricted but includes thesame ones as those already mentioned hereinabove.

It is preferred, however, that the above black matrix be a conductiveone and that the above conductive stage comprise one or more parts eachsmaller in size than the frame-like periphery of each display area onthe substrate. In that case, the number of spacers disposed in theperipheral region of the substrate can be more reliably prevented fromdecreasing.

FIG. 12 is a schematic view, on a horizontal plane and in section,illustrating the picture frame-like state of the black matrix on anordinary common electrode substrate in the method for producing a liquidcrystal display device according to the present invention. At least oneof the first substrate and the second substrate to be disposedopposingly over the first substrate is a color filter substrate for LCDproduction and a black matrix is formed thereon, as shown in FIG. 12.The black matrix demarcates pixels in a latticework manner within thedisplay area. Further, in FIG. 12, parting lines are provided and theregions outside the parting lines constitute a dummy electrode regioncomprising dummy electrodes provided outside the display area on thesubstrate. The parting lines serves as basis lines in cutting the firstand second substrates after alignment thereof.

In some cases, at a dummy electrode site or sites outside the pictureframe state region of the above black matrix, there may remain a blackmatrix as a solid mask. In that case, the position of the black matrixand the region comprising the transparent electrodes are almostidentical with each other, as schematically shown in section in FIG. 12.

In a color filter substrate for LCD production having such constitution,even the use of a smaller conductive stage than the region in which aconductive black matrix is formed results in extension of the effect ofthe earthed conductive stage to the whole black matrix region, wherebythe electric potential of the conductive black matrix lowers.Accordingly, the conductive black matrix region can relay the effect ofthe conductive stage.

Therefore, even when the conductive stage is smaller than the substrate,an electric field suited for spacer positioning is formed in the regionwhere the conductive black matrix exists.

Since, on that occasion, the region outside the conductive black matrixpicture frame is not earthed, the electric potential of the glassportion of the substrate is influenced by the voltage applied to thetransparent electrodes and increases in the direction such that theelectric potential approaches the electric potential of the transparentelectrodes. The state in which the region outside the picture frameregion of the conductive black matrix is not earthed corresponds, forexample, to the case where the conductive black matrix, though present,is divided by parting lines, or the case where there is no conductiveblack matrix portion outside the conductive black matrix picture frame.

When the electric potential within the display area is compared withthat outside the display area in such state, there exist within thedisplay area a high electric potential due to the high voltage appliedto the transparent electrodes and a low electric potential betweenrespective two neighboring transparent electrodes.

On the other hand, outside the display area, when dummy electrodes areformed, as shown in FIG. 13, the dummy electrodes and the glass portionof the substrate both have a high electric potential. Therefore, as faras the whole substrate is concerned, a high electric potential region isformed outside the display area and a low electric potential regionwithin the display area.

As a result, the high electric potential region outside the display areaserves as a wall against the repulsive force and inhibits spacersoccurring within the display area from escaping out of the display area,whereby the number of spacers becomes uniform within the display area,which results in a uniform cell thickness and a uniform displayperformance of the product liquid crystal display device.

Even in cases where the substrate onto which spacers are to be sprayedis of the gang printing type, namely it has a plurality of display areasformed thereon, the same effects as mentioned above can be produced forall display areas, if the black matrix is conductive, by providing aplurality of conductive stages each having a size such that it is withinthe periphery of the picture frame region of the black matrix of eachdisplay area.

In the above case, a plurality of separate conductive stagescorresponding to the plurality of display areas may be provided or aplurality of separate conductive stages may be formed by providing onesingle conductive stage with grooves.

The area of contact between the above conductive stage and the substrateis preferably not less than 30% of the display area or areas.

When a conductive black matrix has been formed as mentioned above, anelectric field suited for spacer positioning is formed over the displayarea even when a conductive stage smaller in size than the matrix regionis provided. This is because the conductive black matrix takes on theeffect of the conductive stage.

If the area of contact between the conductive stage and the display area(black matrix region) is too small, however, the effect of earthing maybecome diminished. Therefore, for forming an electric field suited forspacer disposition in the display area, the area of contact between theconductive stage and the substrate should preferably be not less than30% of the display area or areas on the substrate. If it is less than30%, the effect of earthing will become weak and the electric fieldsuited for spacer disposition will break down and it will becomedifficult to accomplish spacer positioning in the peripheral region ofeach display area.

The method of LCD production according to the fourth aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes and an alignment layer and a second substrate to be disposedopposingly above the first substrate and filling a liquid crystal intothe space between both the substrates comprises the step of removingwater from the substrate onto which spacers are to be sprayed and thestep of bringing the substrate into close contact with an earthedconductive stage and spraying spacers while applying a voltage of thesame polarity as the spacer charge polarity to the transparentelectrodes on the substrate.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe fourth aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

As explained in relation to the third aspect of the invention, inspraying charged spacers in the production of STN type liquid crystaldisplay devices, for instance, the spacers can be disposed in the gapsbetween the respective two transparent electrodes by means of arepulsive force by disposing the substrate comprising at leastpattern-forming transparent electrodes and an alignment layer in closecontact with an earthed conductive stage and applying a voltage of thesame polarity as the spacer charge polarity to the transparentelectrodes on the substrate. In this case, an electric field suited forspacer disposition can be formed by bringing the substrate in closecontact with the earthed conductive stage, as shown in FIG. 1.

The above stage is required to have a volume resistance of not more than10¹⁰ Ωcm and the above substrate may be in close contact with the stageat least over a certain proportion of the surface area thereof.

In the case of STN type liquid crystal display devices, the spacerspraying is generally carried out after the step of rubbing. Since, inthe rubbing step, the alignment layer surface is rubbed with acloth-like synthetic resin or the like wound around a drum, a fibrousmatter from the cloth may adhere to the substrate and, thus, thesubstrate may be sumitted to washing with water following the rubbingstep. This water is blown off by means of an air knife, for instance.However, the substrate is not sufficiently dried in that case.

Even with a sufficiently dried substrate, a certain amount of moistureadheres to the substrate with the lapse of time, since moisture existsin the air. In that case, the amount of adhering moisture varies as thetemperature and/or other factors vary.

In selectively disposing spacers by applying a voltage to thetransparent electrodes, a high voltage of several hundred to severalthousand volts is applied to the transparent electrodes. Therefore, whenspacer disposition onto such a substrate with moisture adhering theretoas mentioned above is attempted in such a state as shown in FIG. 1, amicrocurrent leaks, owing to the presence of the moisture, to the stageside via the moisture on the substrate surface at sites where noalignment layer is formed (sites at which an electrode is exposed) or atsites where an alignment layer is formed but is very thin, for instance,as shown in FIG. 14.

Upon occurrence of such leak, the electric field to be utilized forspacer disposition changes from such a state as shown in FIG. 1 to astate in which the conductive stage itself assumes an increased electricpotential close to the electric potential of the electrodes due tostatic induction so that the interelectrode electric potential will notdecrease. A state close to such a state as shown in FIG. 15 will thusresult, hence an effective electric potential distribution cannot beobtained and selective spacer disposition is no longer possible.

Furthermore, if the substrate surface is covered with moisture, theinterelectrode gap resistance reduces even when the substrate side andthe stage side are insulated from each other. Therefore, while, in a drystate, such an electric potential distribution as shown in FIG. 1 isattained, the electric potential distribution in the presence ofmoisture becomes one such as shown in FIG. 16, which is nearly uniformand reduces the selectivity of spacer disposition.

Even when spacers are sprayed under the same voltage applicationconditions and under the same spraying conditions, different states ofspacer disposition will result since the moisture adhesion to thesubstrate varies according to the environmental humidity and temperatureand so forth, leading to variations in the electric field to be utilizedfor spacer disposition.

Generally, the temperature and humidity in the process of LCD productionare controlled to a certain extent. However, they are subject toseasonal fluctuations, for instance. The amount of adhering moisturechanges also depending on the time from washing with water followingrubbing to spraying or on the extent of drainage, for instance.Therefore, such changes in the amount of adhering moisture as resultingfrom the differences in environment, process step and so forth causevariations in spacer disposition state, hence variations in displayperformance of product liquid crystal display devices.

Further, even though the amount of adhering moisture can be maintainedconstantly at a certain level, it goes without saying that the smallerthe moisture quantity on the substrate is, the easier the formation ofan electric field suited for spacer disposition is. Therefore, byproviding a step of removing moisture from the substrate onto whichspacers are to be sprayed to thereby stably form an electric fieldsuited for spacer disposition, it becomes possible to improve theselectivity of spacer positioning and stably produce liquid crystaldisplay devices excellent in contrast and display uniformity.

The step of removing moisture from the substrate onto which spacers areto be sprayed can be carried out by heating the substrate prior tospraying. It may also be carried out by heating the substrate duringspraying. Further, it may also be conducted by heating the substrateprior to spraying and heating it during spraying as well.

The substrate heating can be effected by means of an oven, hot plate orthe like or by infrared heating, for instance, without any particularrestriction provided that the substrate temperature can be increased. Asthe substrate temperature increases, the adhering moisture decreases, sothat the substrate surface resistance increases; thus, no current leakoccurs any more and stable and highly accurate spacer dispositionbecomes possible.

The heating temperature in the above substrate heating is preferably notlower than 50° C. If it is below 50° C., the moisture removing effectwill be low. A heating temperature of 90° C. or above is more preferred.The effect of substrate heating varies depending on the heatingtemperature and time and, therefore, it is necessary to properly selectthe method of heating and the heating temperature according to theenvironmental humidity and the amount of adhering moisture.

When the time from heating to spacer spraying is too long, moisture mayagain adhere to the substrate after cooling in some instances, thoughsuch situation depends on the environmental humidity. Therefore, spacerspraying is preferably carried out immediately after heating.

However, a certain period of time is required for cooling, since whenthe substrate, while still hot, is disposed on the stage, the substratemay possibly become warped in the process of cooling in certaininstances, leading to a worsened state of spacer disposition due toinsufficient contact with the stage.

The above-mentioned substrate heating during spraying can be effected,for example, by maintaining the stage in a hot plate-like state or bydisposing an infrared heating device within the spray chamber.

The above-mentioned step of removing moisture from the substrate ontowhich spacers are to be sprayed can also be carried out in the manner ofair blowing by blowing a drying gas on the upper and lower surfaces ofthe substrate. The adhering moisture can be reduced by sufficientlyblowing a drying gas on the upper and lower surfaces of the substrate.The drying gas is preferably in a dry state as close as possible to anabsolute dry condition.

It is also preferred that the above drying gas be at a temperature notlower than room temperature. In the case of air blowing at a temperaturebelow room temperature, the gas used, even when it is in a drycondition, deprives heat from the substrate, whereby the substratetemperature falls, whereupon moisture resulting from condensation maypossibly adhere to the substrate.

Usable as the drying gas are dry nitrogen gas, dry air and the like.

The above step of removing moisture from the substrate onto whichspacers are to be sprayed can also be carried out by replacing themoisture with a solvent. For example, the current leak to the stage canbe reduced by wiping the back of the substrate and the peripheral regionof the substrate with a solvent. The moisture can also be removed bydipping (immersing) the substrate in a solvent, followed by drying.Further, the drying time can be reduced and the tact time in theproduction process can be shortened by replacing the moisture with asolvent and then drying under heating. The solvent is not particularlyrestricted but one miscible with water and having a low boiling point,such as acetone, is preferred.

The above step of removing moisture from the substrate onto whichspacers are to be sprayed can also be carried out by allowing thesubstrate to stand under vacuum or heating the same under vacuum. Thus,moisture removal can be effected by allowing the substrate under vacuumand more efficiently by heating the same under vacuum. For allowing thesubstrate under vacuum, a vacuum drier, for instance, can judiciously beused.

For confirming the moisture removal from the substrate in the abovestep, an electrometer or the like is provided between the transparentelectrodes and the conductive stage, as shown in FIG. 17, and apreferred criterion for that purpose is that when a voltage of 1 kV isapplied to the transparent electrodes after the above-mentioned step ofmoisture removal, the current flowing between the transparent electrodesand the conductive stage is not more than 10⁻⁶ A.

In providing the above-mentioned electrometer or the like, theelectrodes for voltage application may be utilized or separateelectrodes may be provided. The electrodes may have any shape, forexample a needle-like shape or a flat sheet shape, and the electrodematerial maybe any conductive material. For example, contact probes fortesting purposes may be used as the electrodes.

It is necessary that the above electrodes be provided so as not tobecome obstacles in inserting the substrate into the sprayer. Thisinsertion of the substrate into the sprayer can be facilitated, forexample, by providing a mechanism enabling an up-and-down motion of thesubstrate or the electrodes.

In cases where the substrate surface has adhering moisture, amicrocurrent flows upon application of a voltage to the transparentelectrodes as mentioned above, hence no electric field suited for spacerdisposition is formed any longer. Therefore, if the current flowingbetween the transparent electrodes and the conductive stage onapplication of a voltage of 1 kV to the electrodes is greater than 10⁻⁶A, an electric field suited for spacer disposition is hardly produced,hence the selectivity of spacer disposition tends to decrease. When thecurrent is not greater than 10⁻⁶ A, an electric field favorable forspacer positioning is formed and the spacers show highly selectivepositioning.

As mentioned above, if when a voltage of 1 kV is applied to thetransparent electrodes, the current flowing between the transparentelectrodes and the conductive stage is greater than 10⁻⁶ A, an electricfield favorable for spacer disposition is hardly produced, hence theselectivity of spacer disposition may reduce. It is possible, however,to employ substrate voltage measurements in lieu of the electrometer byutilizing the fact that a higher current leads to a reduction intransparent electrode voltage due to voltage drop. In this case, avoltmeter having a sufficiently high input resistance is disposed in thesame manner as the electrometer for confirming that the measured valueobtained by the voltmeter be equal to the applied voltage within theprecision or error of measurement.

It is to be noted that, in spacer disposition, it is not necessary toapply a voltage of 1 kV to the transparent electrodes. That the currentflowing between the transparent electrodes and the conductive stage isnot more than 10⁻⁶ A serves only as a criterion for confirming thatmoisture has been removed.

In carrying out the method of LCD production comprising disposingspacers at black matrix sites while applying a voltage of the samepolarity as the spacer charge polarity to the transparent electrodes, itwas a problem that even when the same conditions and same substratespecies are used, the percentage of spacer disposition at black matrixsites is always variable and depends on the time and situation. As aresult of an intensive investigation of the cause thereof, it was foundthat the selectivity of spacer positioning at black matrix sites variesunder the influence of the moisture in the environment (air). Therefore,by providing a step of removing moisture from the substrate onto whichspacers are to be sprayed, it becomes possible to improve the insulationperformance, eliminate the leakage current from the transparentelectrodes and stably form an electric field for spacer positioning. Asa result, it becomes possible to dispose spacers at black matrix siteswith good yield and high precision.

The method of LCD production according to the fifth aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes and an alignment layer and a second substrate to be disposedopposingly above the first substrate and filling a liquid crystal intothe space between both the substrates comprises the step of disposingthe substrate in close contact with an earthed conductive stage andspraying spacers while applying a voltage of the same polarity as thespacer charge polarity to the transparent electrodes on the substrate,wherein the substrate before and during spacer spraying showscharacteristics such that when a voltage of 1 kV is applied to thetransparent electrodes on the substrate, the current flowing between thetransparent electrodes on the substrate and the conductive stage is notmore than 10⁻⁶ A.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe fifth aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

As explained in relation to the fourth aspect of the invention, theadhesion of moisture to the substrate varies depending on theenvironmental humidity and temperature, among others. Therefore, evenwhen spacers are sprayed under the same voltage application conditionsand the same spraying conditions, the electric field to be utilized inspacer disposition varies, hence different states of spacer dispositionresult.

Therefore, by disposing the substrate in close contact with an earthedconductive stage and spraying spacers in interelectrode gaps with highaccuracy and in a stable manner by applying a voltage of the samepolarity as the spacer charge polarity to the substrate electrodes, itis necessary to check and control the moisture on the substrate.

As mentioned hereinbefore, the moisture condition on the substrate canbe checked, for example, by providing an electrometer or the likebetween the transparent electrodes and the conductive stage, as shown inFIG. 17.

The method of checking by providing an electrometer or the like in theabove manner comprises applying a voltage to the transparent electrodeson the substrate onto which spacers are to be sprayed and measuring thecurrent flowing between the transparent electrodes and the conductivestage. On that occasion, if the substrate is in a moistened state underthe influence of the humidity and so forth, the leakage current flowingfrom the transparent electrodes to the stage will be strong and, if thesubstrate is in a dry state, the leakage current will be weak.

Therefore, for checking the amount of moisture adhering to the substratebefore spraying as well as during spraying, a voltage of 1 kV is appliedto the transparent electrodes and the current flowing between thetransparent electrodes and the conductive stage is checked by means ofan electrometer or the like. When the microcurrent flowing between thetransparent electrodes and the conductive stage is controlled byrestricting the current to not more than 10⁻⁶ A, the spacer positioningis stabilized.

It is not necessary that the voltage to be applied to the transparentelectrodes for spacer disposition be equal to 1 kV. The sole purpose ofusing a voltage of 1 kV is to check the moisture content by confirmingthat, at this voltage, a current not greater than 10⁻⁶ A will flowbetween the transparent electrodes and the conductive stage.

The above method of LCD production is preferably carried out bycontrolling, in the step of disposing the substrate in close contactwith an earthed conductive stage and spraying spacers while applying avoltage of the same polarity as the spacer charge polarity to thetransparent electrodes on the substrate, the temperature and relativehumidity within the ranges of room temperature (18° C. to 28° C.) andnot more than 50%, respectively, so that the current flowing between thetransparent electrodes and the conductive stage may be restricted to notmore than 10⁻⁶ A.

Furthermore, in storing the above substrate, for instance, the substrateis preferably kept in an environment at room temperature (18° C. to 28°C.) and at a relative humidity of not more than 50%.

When the relative humidity is not more than 50% but the temperature islower than room temperature (18° C.), the temperature is excessivelylower than the working environment and may rather cause condensation ofthe moisture. When the relative humidity is not more than 50% but thetemperature is higher than room temperature (28° C.), the environment isunsuitable as the working environment. Further, when the relativehumidity is higher than 50%, the moisture in the air is excessive,causing constant adherence of moisture to the substrate and making itdifficult to realize high precision spacer disposition.

In carrying out the method of LCD production comprising disposingspacers at black matrix sites by applying a voltage of the same polarityas the spacer charge polarity to the transparent electrodes, it becomespossible to dispose spacers at black matrix sites in a high yield andwith high accuracy when the moisture on the substrate onto which spacersare to be sprayed is controlled to thereby cause stable formation of anelectric field for spacer disposition.

The method of LCD production according to the sixth aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrodes and an alignment layer and a second substrate to be disposedopposingly above the first substrate and filling a liquid crystal intothe space between both the substrates comprises disposing, in sprayingpositively or negatively charged spacers onto the substrate, thesubstrate into close contact with an earthed conductive stage, applyinga voltage of the same polarity as the spacer charge polarity to thetransparent electrodes on the substrate, then removing, from thetransparent electrodes, the terminals of the voltage applicationapparatus, and carrying out spacer spraying while the electric chargeremains on the substrate.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe sixth aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

As explained in relation to the third aspect of the invention, inspraying charged spacers in the production of STN type liquid crystaldisplay devices, for instance, the spacers can be disposed in the gapsbetween the respective two transparent electrodes by means of arepulsive force by disposing the substrate comprising at leastpattern-forming transparent electrodes and an alignment layer in closecontact with an earthed conductive stage and applying a voltage of thesame polarity as the spacer charge polarity to the transparentelectrodes on the substrate. In this case, an electric field suited forspacer disposition can be formed by bringing the substrate in closecontact with the earthed conductive stage, as shown in FIG. 1.

The above stage is required to have a volume resistance of not more than10¹⁰ Ωcm and the above substrate may be in close contact with the stageat least over a certain proportion of the surface area thereof. If thevolume resistance is higher than the above value, the whole substratewill have an electric potential close to that of the transparentelectrodes and, as a result, the positioning accuracy will becomedeteriorated.

Here, when the substrate is disposed in close contact with the earthedconductive stage and a voltage of the same polarity as the spacer chargepolarity is applied to the pattern-forming transparent electrodes on thesubstrate onto which spacers are to be sprayed, as shown in FIG. 18, anelectric field suited for spacer disposition is formed. Then, theterminals of a voltage application apparatus are removed from thetransparent electrodes, whereupon an electric charge is accumulated oneach transparent electrode and the charge remains for a certain periodof time.

Thus, an electric field suited for spacer disposition is maintained fora certain period of time. When spacers are sprayed in that state, thespacers can be disposed between the respective neighboring transparentelectrodes.

On that occasion, it is necessary to remove the terminals from thevoltage application apparatus from the transparent electrodes whileapplying a voltage of the same polarity as the spacer charge polarity tothe pattern-forming transparent electrodes. If the voltage applicationis discontinued without removing the terminals, the electric charge willflow out via the voltage application apparatus and, as a result, anyelectric field suited for spacer disposition will not be obtained anylonger.

The above conductive stage (also referred to as table), which movestogether with the substrate, may be a plate-like one or a film- orsheet-like one, such as an aluminum foil, provided that it is earthed atthe time of voltage application.

The application of a voltage of the same polarity as the spacer chargepolarity to the pattern-forming transparent electrodes is preferablycarried out over a certain period of time. A longer period of voltageapplication results in an increased electric charge accumulation, hencein a prolonged duration of the effect after removal of the terminalsderived from the voltage application apparatus.

When spacer spraying is carried out while applying a voltage of 2.0 kV,for instance, and the disposition at that voltage is confirmed to beappropriate, it is preferred that a little higher voltage, for example2.5 kV, be applied in employing the method according to the seventhaspect of the present invention.

This is because, since the electric charge attenuates with the lapse oftime, it is necessary to take the attenuation into consideration.

Further, the earthed conductive stage is a mobile one. Thus, by settingthe substrate in close contact with the earthed conductive stage,applying a voltage of the same polarity as the positively or negativelycharged spacer to the transparent electrodes on the substrate,disconnecting the terminals of a voltage application apparatus from thetransparent electrodes, causing the conductive stage and substrate heldin intimate contact to move into the sprayer, and applying a voltage onthe earthed conductive stage, an electric field suited for spacerdisposition can be formed to thereby dispose the spacers into the gapsbetween the transparent electrodes.

Upon removal of the terminals derived from the voltage applicationapparatus while still applying a voltage of the same polarity as thespacer charge polarity to the transparent electrodes on the substrate,an electric charge remains on the substrate and an electric field suitedfor spacer disposition is maintained. Here, as long as the substrate andthe conductive stage are kept in close contact, the electric fieldformed is maintained for insuring adequate spacer positioning, whetherthe “table plus substrate” is positioned after movement in an earthedsite or in an insulated site.

Therefore, as shown in FIG. 19, the step of voltage application withinthe sprayer can be omitted and the tact time curtailed by applying avoltage to the transparent electrodes on the earthed conductive stagebefore the step of spacer spraying and feeding the table together withthe transparent electrodes into the sprayer. In other words, the step ofvoltage application to the next substrate onto which spacers are to besprayed can be finished during spacer spraying onto the precedingsubstrate within the sprayer and thus high contrast liquid crystaldisplay devices free of spacers in the display portions can be producedwith a high degree of efficiency.

The method of LCD production according to the seventh aspect of thepresent invention comprising spraying spacers onto at least one of afirst substrate comprising at least pattern-forming transparentelectrode and an alignment layer and a second substrate to be disposedopposingly above the first substrate and filling a liquid crystal intothe space between both the substrates comprises disposing, in sprayingpositively or negatively charged spacers onto the substrate, thesubstrate into close contact with an earthed conductive stage, applyinga voltage of the same polarity as the spacer charge polarity to thetransparent electrodes on the substrate, maintaining that state ofvoltage application for a certain period of time and then carrying outspacer spraying while maintaining that state of voltage application.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. As explained in relation to thefirst aspect of the invention, the method of LCD production according tothe seventh aspect of the invention can be applied to the production ofTFT type liquid crystal display devices.

As explained in relation to the third aspect of the invention, inspraying charged spacers in the production of STN type liquid crystaldisplay devices, for instance, the spacers can be disposed in the gapsbetween the respective two transparent electrodes by means of arepulsive force by disposing the substrate comprising at leastpattern-forming transparent electrodes and an alignment layer in closecontact with an earthed conductive stage and applying a voltage of thesame polarity as the spacer charge polarity to the transparentelectrodes on the substrate. In this case, an electric field suited forspacer disposition can be formed by bringing the substrate in closecontact with the earthed conductive stage, as shown in FIG. 1.

The above stage is required to have a volume resistance of not more than10¹⁰ Ωcm and the above substrate may be in close contact with the stageat least over a certain proportion of the surface area thereof. If thevolume resistance is higher than the above value, the whole substratewill have an electric potential close to that of the transparentelectrodes and, as a result, the positioning accuracy will becomedeteriorated.

Upon voltage application to the transparent electrodes on the substratein a state such that the substrate is disposed on the earthed conductivestage, the substrate is electrostatically brought into close contactwith the conductive stage.

In that case, it is presumable that, at the moment of voltageapplication, an air layer occurs between the substrate and theconductive stage, hence no perfectly close contact has been attained asyet.

Here, an electric field suited for spacer disposition is formed by thesubstrate coming into close contact with the conductive stage.Therefore, when an air layer, which is an insulating layer, occursbetween the substrate and the conductive stage, the electric potentialbetween the respective neighboring transparent electrodes will notdecrease to a sufficient extent, hence the spacer positioning accuracytends to deteriorate.

During voltage application to the transparent electrodes, the conductivestage and the substrate are electrostatically attracted to each other.This electrostatic force gradually eliminates the air and a state ofhighly close contact is attained between the conductive stage and thesubstrate, and an electric field suited for spacer disposition is formedstably.

In that case, the state of voltage application is preferably maintainedfor at least five seconds since, in this case, the air is sufficientlyeliminated from between the conductive stage and the substrate, with theresult that a stably high level of spacer positioning accuracy can besecured.

The method of LCD production according to the eighth aspect of thepresent invention comprising spraying spacers onto a first substratecomprising at least pattern-forming transparent electrodes, a conductiveblack matrix, an overcoat layer and an alignment layer, and filling aliquid crystal into the space between the first substrate and a secondsubstrate comprising thin film transistors formed thereon, which is tobe disposed opposingly above the first substrate comprises using, as thefirst substrate, a substrate having transparent electrode-free etchedregions formed within the transparent electrodes over and within theexpanse of the corresponding conductive black matrix areas, and, inspraying positively or negatively charged spacers onto the firstsubstrate, applying a voltage (V1) to the conductive black matrix and avoltage (V2) to the transparent electrodes, wherein both the voltages V1and V2 are positive ones and satisfying the relation V1<V2 when thespacer charge polarity is positive, or both V1 and V2 are negativevoltages and satisfying the relation V1>V2, when the spacer chargepolarity is negative.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention.

The above conductive black matrix and overcoat layer are the same asmentioned hereinabove referring to the second aspect of the invention.

On the above-mentioned first substrate, there are formed, within eachtransparent electrode, transparent electrode-free etched regions overand within the expanse of the corresponding conductive black matrixareas, as shown in FIG. 20.

FIGS. 20 to 23 each is a schematic view illustrating a first substratewith such etched areas formed thereon.

These etched areas, as shown in FIGS. 20 to 23, are formed by performingetching the transparent electrodes in a predetermined pattern over andwithin the expanse of the corresponding conductive black matrix areas.

The etched areas may be over and within the expanse of the correspondinglinear conductive black matrix portions arranged in the horizontaldirection or the direction perpendicular thereto, or over and within theexpanses of the crossing portions of the black matrix, for instance.They are not restricted in shape but may be linear, rectangular (FIGS.20 and 23), circular, cross-shaped (FIG. 21) or stripe-like (FIG. 22),for instance. The frequency of appearance of etched areas is notparticularly restricted, either. Thus, they may each appear per dotpitch, per pixel pitch and/or per several pixels, in the horizontaland/or vertical direction.

In TFT type liquid crystal display devices, a first substrate havingcolor filters is generally used as a common electrode and thetransparent electrodes are formed as a solid electrode. In the firstsubstrate, a voltage is applied to the solid electrode, and the voltagecontrol of the respective pixels is carried out by using thin filmtransistors and transparent electrodes formed on a second substrate.

Therefore, even when etched areas are formed on the solid electrode byetching, a voltage is applied to the display areas quite in theconventional manner in the liquid crystal display device assembled,hence no adverse influence is exerted on the display performance.

In accordance with the eighth aspect of the invention, in sprayingpositively or negatively charged spacers onto the first substrate, avoltage (V1) is applied to the black matrix and a voltage (V2) to thetransparent electrodes.

As for the voltage species, the same explanation as made referring tothe first aspect of the invention applies.

By applying a voltage (V1) to the conductive black matrix and a voltage(V2) to the transparent electrodes, it is possible to form an electricfield suited for spacer disposition, as shown in FIG. 2, like the caseshown in FIG. 1, without requiring disposing the substrate in closecontact with a conductive stage having a volume resistance of not morethan 10¹⁰ Ωcm.

When the spacer charge is positive, for instance, positive voltages areused as both voltages to be applied, with the condition V1<V2, whereby astronger repulsive force is produced over the transparent electrodes anda weaker repulsive force over the black matrix sites, so that spacerscan be disposed at black matrix sites (in the case of negative spacercharge as well, the situation is the same).

The reason why the above V1 and V2 and the spacer charge should have thesame polarity is as follows. For controlling the spacer fallingpositions with high accuracy, a repulsive force of around 1 kV isrequired. If, here, V1 and V2 are different in polarity, the potentialdifference between the transparent electrodes and the black matrixbecomes about 1 kV. Since the overcoat layer is as thin as 2 to 5 μm,short-circuiting occurs between the transparent electrodes and the blackmatrix and, thus, any electric field suited for spacer positioning is nolonger formed. Therefore, the potential difference between V1 and V2 ispreferably within 100 V. Spacer position control can be accomplishedwith success even when the potential difference is thus small, namelynot more than 100 V, for this is a potential difference in the repulsivephase.

As for the relation between V1 and V2, the same explanation. as madereferring to the second aspect of the invention applies.

The method of LCD production according to the ninth aspect of thepresent invention comprising spraying spacers onto a first substratecomprising at least pattern-forming transparent electrodes, a blackmatrix, an overcoat layer and an alignment layer, and filling a liquidcrystal into the space between the first substrate and a secondsubstrate comprising thin film transistors formed thereon, which is tobe disposed opposingly above the first substrate, comprises using, asthe first substrate, a substrate having transparent electrode-freeetched regions formed within the transparent electrodes over and withinthe expanse of the corresponding conductive black matrix areas, and, inspraying positively or negatively charged spacers onto the firstsubstrate, disposing the first substrate into close contact with anearthed conductive stage having a volume resistance of not more than10¹⁰ Ωcm and applying, to the transparent electrodes, a voltage of 200 Vto 5 kV having the same polarity as the spacer charge polarity.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. The overcoat layer is the same asmentioned hereinabove referring to the second aspect of the invention.

By disposing the substrate in close contact with the earthed conductivestage, which has a volume resistance of not more than 10¹⁰ Ωcm, theelectric potential between the respective transparent electrodes lowers,as shown in FIG. 2, and an electric field suited for spacer dispositionis formed in the same manner as shown in FIG. 1, with the result thatspacers are disposed in etched areas (interline areas).

The voltage to be applied to the above transparent electrodes is 200 Vto 5 kV. At a voltage below 200 V, a potential difference sufficient forachieving spacer position control may not be produced. At a voltageexceeding 5 kV, short-circuiting may readily occur between thetransparent electrodes and the conductive black matrix.

As for the voltage species, the same explanation as made referring tothe first aspect of the invention applies.

In spraying charged spacers according to the ninth aspect of theinvention, the electric field formed over the transparent electrodesexerts a repulsive force against the charge polarity of spacers, so thatthose spacers sprayed over the periphery of the first substrate canreadily escape outside. Thus, the number of spacers disposed on theperiphery of the first substrate tends to decrease.

Generally, transparent electrodes are formed only in the display area ofthe first substrate. In the eighth and ninth aspects of the invention,however, it is preferred that transparent electrodes be formed outsidethe display area as well and that the same voltage as that in thedisplay area be applied thereto. By doing so, the decrease in number ofspacers occurs only outside the display area and spacers are disposeduniformly within the display area.

The method of LCD production according to the tenth aspect of thepresent invention comprising spraying spacers onto a first substratecomprising at least pattern-forming transparent electrodes, and fillinga liquid crystal into the space between the first substrate and a secondsubstrate comprising thin film transistors formed thereon, which is tobe disposed opposingly above the first substrate, comprises using, asthe first substrate, a substrate having isolated, electrically floating,transparent electrodes not connected with the surrounding transparentelectrodes but formed within the transparent electrodes within theexpanse of the corresponding black matrix areas as formed on the firstor second substrate, and, in spraying positively or negatively chargedspacers onto the first substrate, disposing the first substrate intoclose contact with an earthed conductive stage having a volumeresistance of not more than 10¹⁰ Ωcm and applying a voltage of the samepolarity as the spacer charge polarity to the transparent electrodesother than the isolated transparent electrodes on the first substrate.

In the first substrate for constituting a TFT type liquid crystaldisplay device, it is a general practice to form a color filter layer ona glass substrate and a black matrix, then form an overcoat layer of aninsulating material on the color filter layer and further form thereontransparent electrodes and an alignment layer (not shown), as shown inFIG. 2. In the description that follows, the first substrate is to beconstrued as having the above constitution.

The transparent electrodes, substrates, spacers and spacer chargingmethod mentioned above are the same as mentioned hereinabove referringto the first aspect of the invention. The black matrix is notparticularly restricted on condition that it has a light blockingeffect. It may be made of chromium, aluminum, carbon black or a pigment,for instance.

The overcoat layer is the same as that mentioned hereinabove referringto the second aspect of the invention.

Within the transparent electrodes on the above first substrate, thereare formed isolated, electrically floating, transparent electrodes notconnected with the surrounding electrodes in a manner such that they arelocated within the expanse of the corresponding black matrix-formingareas, as shown in FIG. 24.

FIGS. 25 to 28 each is a schematic view illustrating the first substratehaving such isolated transparent electrodes formed thereon.

As shown in FIGS. 25 to 28, these isolated transparent electrodes areformed by etching in a predetermined width around the contemplatedtransparent electrode areas. Each etched zone thus formed by etchingpreferably has a width (distance between the corresponding transparentelectrode and the isolated transparent electrode) of not less than 3 μm,more preferably not less than 5 μm. If the etched zone width is lessthan 3 μm, short-circuiting may readily occur between the correspondingtransparent electrode and the isolated transparent electrode.

The sites at which isolated transparent electrodes are formed may bewithin the expanse of the corresponding linear black matrix-formingregions arranged in the horizontal direction or the directionperpendicular thereto, or within the expanse of the corresponding blackmatrix-forming crossing portions, for instance. They are not restrictedin shape but may be linear, rectangular (FIGS. 25 and 28), circular,cross-shaped (FIG. 26) or stripe-like (FIG. 27), for instance. Thefrequency of appearance of the isolated transparent electrodes is notparticularly restricted, either. Thus, they may each appear per dotpitch, per pixel pitch and/or per several pixels, in the horizontaland/or vertical direction.

In the TFT type liquid crystal display device according to the tenthaspect of the invention, like in the one described referring to theeighth aspect of the invention, even when isolated transparentelectrodes are formed within a solid electrode by etching, a voltage isapplied to the display area of the liquid crystal display deviceassembled in the same manner as in the prior art and no adverse effectis produced on the display performance.

The first substrate having transparent electrodes and isolatedtransparent electrodes in the above mode is brought into close contactwith an earthed conductive stage having a volume resistance of not morethan 10¹⁰ Ωcm and spacer spraying is carried out while applying avoltage of the same polarity as the spacer charge polarity to othertransparent electrodes than the isolated transparent electrodes on thefirst substrate.

By disposing the substrate in close contact with the earthed conductivestage having a volume resistance of not more than 10¹⁰ Ωcm, the electricpotential of the gaps between the respective transparent electrodeslowers, as shown in FIG. 24, and an electric field suited for spacerpositioning is formed, in the same manner as shown in FIG. 1, andspacers are disposed on the isolated transparent electrodes.

The voltage required for spacer disposition is preferably about 200 V to5 kV, although it depends on the spacer diameter and/or the chargethereon. At a voltage exceeding 5 kV, when the black matrix isconductive, short-circuiting may readily occur between the transparentelectrodes and the conductive black matrix and even between thetransparent electrodes and the isolated transparent electrodes, leadingto a reduced yield. At below 200 V, spacers falling down in the step ofspraying will arrive at the substrate surface before their making anecessary turn, hence the spacer positioning accuracy may be decreased.

The amount of electric charge on the spacer may be the same as mentionedreferring to the second aspect of the invention.

In spraying charged spacers, the electric charge formed over thetransparent electrodes acts as a repulsive force against the spacercharge polarity, so that those spacers sprayed over the periphery of thefirst substrate can readily escape outside the same. Therefore, thenumber of spacers disposed on the periphery of the first substrate showsa tendency to decrease.

While, generally, transparent electrodes are formed only in the displayarea, it is preferred, in the practice of the tenth aspect of theinvention, that transparent electrodes be formed outside the displayarea as well and that the same voltage as that applied to the displayarea be applied to the transparent electrodes outside the display area.In this arrangement, the decrease in the number of spacers occurs onlyoutside the display area and spacers are disposed uniformly within thedisplay area.

The method of LCD production according to the eleventh aspect of theinvention, which is as defined in the first, second, third, fourth,fifth, sixth, seventh, eighth, ninth or tenth aspect of the invention,comprises charging spacers positively or negatively by spraying themthrough a pipeline made of a resin or a metal using a gas as a medium,whereby the amount of charge on each spacer to be sprayed is increasedas compared with the wet method of spraying and the precision of spacerpositioning on the substrate is improved.

The method of LCD production according to the twelfth aspect of theinvention, which is as defined in the first, second, third, fourth,fifth, sixth, seventh, eighth, ninth, tenth or eleventh aspect of theinvention, comprises fixing spacers on the substrate surface by heating.

By using spacers exhibiting adhesiveness upon heating, for instance, andfixing them on the substrate surface, it is possible to prevent spacersfrom moving after disposition and thus produce a high quality liquidcrystal display device uniform in cell thickness and free of displayunevenness.

As the method of causing spacers to express adhesiveness upon heating,there may be mentioned, among others, the method comprising coveringspacers with a thermoplastic resin layer and the method comprisingintroducing a reactive group onto the spacer surface. It is alsopossible to cause spacers to show adhesiveness upon light irradiation bysome or other means.

The liquid crystal display device according to the thirteenth aspect ofthe invention is one produced by the method of LCD production accordingto the first, second, third, fourth, fifth, sixth, seventh, eighth,ninth, tenth, eleventh or twelfth aspect of the invention. It is uniformin cell thickness and has high quality display performancecharacteristics without showing any unevenness in display.

BEST MODES FOR CARRYING OUT THE INVENTION

The following examples illustrate the present invention in furtherdetail. They are, however, by no means limitative of the scope of theinvention.

EXAMPLE 1

A segment electrode substrate for STN type LCD production (360×460 mmglass substrate with pattern-forming linear transparent electrodesformed thereon; ITO (indium tin oxide) electrode width 80 μm,interelectrode gap 20 μm, glass thickness 0.7 mm) was prepared as thesubstrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

The substrate was of a type for producing two final substrates, namelyit had two display areas formed thereon. All linear transparentelectrodes (ITO electrodes) were connected with one another outside thedisplay areas and connected with a voltage application apparatus so thata direct current voltage might be applied to the ITO electrodes on thesubstrate. The voltage application apparatus could arbitrarily beadjusted with respect to voltage and voltage polarity.

The sprayer used was a dry method sprayer produced by NisshinEngineering Co., as shown in FIG. 29. On an earthed conductive aluminumstage was placed an antistatic mat having a surface resistance of notmore than 10⁷ Ωcm in close contact with the stage, and the substrate wasdisposed thereon in close contact therewith. Further, the voltageapplication apparatus was provided with a connecting terminal forvoltage application and the wire therefrom was introduced into the spraychamber so that a voltage might be supplied to the substrate.

Micropearl BBS-PH (trademark; product of Sekisui Fine Chemical; particlesize: 6.8 μm) were prepared as the spacers.

Then, a voltage of −2.5 kV was applied to all ITO electrodes on thesubstrate. While maintaining this state, the spacers were passed througha stainless steel piping (whereby the spacers were charged negatively(−)) and sprayed onto the substrate using compressed air at a pressureof 1.75 kg/cm². That the spacers were negatively charged was confirmedbeforehand.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers were located in theinterelectrode gaps. Thus, the spacers were found in black matrix sites.

Thereafter, that conductor portion of the spacer-carrying substrate wascut off, followed by the conventional steps of sealing, laminating,substrate cutting, liquid crystal filling and so on, to give a liquidcrystal display device.

EXAMPLE 2

A common electrode substrate for STN type LCD production (glasssubstrate provided with pattern-forming linear transparent electrodes, ablack matrix made of metallic chromium and color filters; aperture sizeof each of RGB pixels =80×280 μm, black matrix line width=35 μm, acrylicresin overcoat layer=3.0 μm, ITO electrode line width=290 μm,interelectrode distance=25 μm, glass thickness=0.7 μm) was prepared asthe substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

The substrate electrodes had such a constitution as shown in FIG. 3.

Using this substrate, the procedure of Example 1 was followed in thesame manner except that a voltage of −2.0 kV was applied to the ITOelectrodes.

Microscopic observation of the substrate having the spacers disposedthereon revealed that the spacers were located in the interelectrodegaps. Thus, they were found at black matrix sites.

EXAMPLE 3

The procedure of Example 1 was followed in the same manner except thatthe antistatic mat was removed and the substrate was disposed directlyon the conductive aluminum stage.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers were located in theinterelectrode gaps. Thus, they were found at black matrix sites.

Comparative Example 1

The procedure of Example 1 was repeated except that plastic pins wereerected on the conductive aluminum stage and the substrate was placedthereon, so that the substrate was kept insulated from the stage by air.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers were located also in thedisplay electrode sites. Thus, the spacers were disposed nearlyrandomly.

Comparative Example 2

The procedure of Example 1 was followed in the same manner except thatthe voltage applied to all ITO electrodes was −1.0 kV.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers were located also in thedisplay electrode sites. Thus, the spacers were disposed nearlyrandomly.

EXAMPLE 4

A dummy electrode-free common electrode substrate for STN type LCDproduction (glass substrate provided with pattern-forming lineartransparent electrodes, a black matrix made of metallic chromium andpigment dispersion type color filters; aperture size of each of RGBpixels=80×285 μm, RGB layer thickness=1.5 μm, metallic chromium blackmatrix line width =20 μm, acrylic resin overcoat layer=3.0 μm, ITOelectrode line width=290 μm, interelectrode distance=15 μm, glassthickness=0.7 mm), as shown in FIG. 3, was prepared as the substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

All ITO electrode ends, on one side, were connected with a voltageapplication tool having a number of needle electrodes, which tool wasconnected with a voltage application apparatus so that a direct currentvoltage might be applied to the ITO electrodes on the substrate.

Further, the black matrix was partly exposed by partly scraping off theITO electrode layer and overcoat layer outside the display area and theexposed parts were connected with another voltage application apparatusso that a direct current voltage might be applied also to the blackmatrix portions. The two voltage application apparatus could each bearbitrarily adjusted with respect to voltage and voltage polarity.

The substrate was placed in the spray chamber in a state insulated fromthe stage in the same manner as in Comparative Example 1.

Micropearl BBS-PH (trademark; product of Sekisui Fine Chemical; particlesize: 5.3 μm) were prepared as the spacers.

Then, a voltage of −2.50 kV was applied to all ITO electrodes on thesubstrate and a voltage of −2.48 kV to the black matrix portions, togive a potential difference of 20 V therebetween. While maintaining thisstate, the spacers were passed through a stainless steel piping (wherebythe spacers were charged negatively (−)) and sprayed onto the substrateusing compressed air at a pressure of 1.75 kg/cm². That the spacers werenegatively charged was confirmed beforehand.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed at blackmatrix sites.

EXAMPLE 5

A substrate constituted in the same manner as that used in Example 4except that linear transparent electrodes and a dummy electrode wereformed on the overcoat layer surface and the linear transparentelectrodes were connected with the dummy electrode, as shown in FIG. 5,was used, and a voltage was applied to the dummy electrode and blackmatrix portions using separate voltage application apparatus. The blackmatrix portions were constituted so as to enable voltage applicationthereto in the same manner as in Example 4.

By applying a voltage to the dummy electrode portion, the same voltagewas applied to the linear transparent electrodes as well. The voltageapplied to the dummy electrode part was −2.50 kV and that applied to theblack matrix portions was −2.48 kV, just as in Example 4. Thereafter,the procedure of Example 4 was followed.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed uniformlyat black matrix sites all over the display area, even in its marginalarea. The state of spacer disposition in the marginal part of thedisplay area was still more improved as compared with Example 4.

Then, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed liquid crystaldisplay device showed high contrast and no display unevenness all overthe display area upon observation of the display on the screen thereof.

EXAMPLE 6

A substrate constituted in the same manner as in Example 2 except thatlinear transparent electrodes and a dummy electrode were formed thereonand the linear transparent electrodes were connected with the dummyelectrode, as shown in FIG. 5, was used and the procedure of Example 2was followed.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed at blackmatrix sites all over the display area and in particular that spacershad been disposed uniformly at such sites in the marginal part of thedisplay area as well. The state of spacer disposition in the marginalpart of the display area was still more improved as compared withExample 4.

Then, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and no display unevenness all over the display area uponobservation of the display on the screen thereof.

EXAMPLE 7

The procedure of Example 2 was followed in the same manner except thatthe voltage applied was −6.0 kV. Discharge, hence short-circuiting,occurred between the ITO electrodes and the black matrix.

EXAMPLE 8

In the procedure of Example 4, a voltage of −2.0 kV was applied to theITO electrodes and +100 V to the black matrix. Discharge, henceshort-circuiting, occurred between the ITO electrodes and the blackmatrix.

EXAMPLE 9

The procedure of Example 1 was followed in the same manner except that adummy electrode was formed in the manner shown in FIG. 5 and all lineartransparent electrodes were connected with the dummy electrode.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed at blackmatrix sites all over the display area and in particular that spacershad been disposed uniformly at such sites in the marginal part of thedisplay area as well. The state of spacer disposition in the marginalpart of the display area was still more improved as compared withExample 1.

Then, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and no display unevenness all over the display area uponobservation of the display on the screen thereof.

EXAMPLE 10

The procedure of Example 2 was followed in the same manner except that asubstrate having a structure such that linear transparent electrodes anda dummy electrode were formed thereon but the linear transparentelectrodes were not connected with the dummy electrode was used and thata voltage of −2.0 kV was applied to all linear transparent electrodes bymeans of a voltage application apparatus comprising bar electrodes and−2.03 kV to the dummy electrode using another voltage applicationapparatus.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed at blackmatrix sites all over the display area and in particular that spacershad been disposed uniformly at such sites in the marginal part of thedisplay area as well.

EXAMPLE 11

A common electrode substrate for STN type LCD production (glasssubstrate provided with pattern-forming linear transparent electrodes, ablack matrix made of a resin and color filters; aperture size of each ofRGB pixels=80×280 μm, black matrix line width=35 μm, acrylic resinovercoat layer =3.0 μm, ITO electrode line width=290 μm, interelectrodedistance=25 μm, glass thickness=0.7 mm) was prepared as the substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

The substrate was of a type for producing two final substrates, namelyit had two display areas formed thereon.

The ITO electrodes were formed with a margin of about 10 mm from eachedge line of the substrate, as shown in FIG. 5 and the dummy electrodewas connected with a voltage application apparatus so that upon voltageapplication to the dummy electrode on the substrate, a direct currentvoltage might be applied to all ITO electrodes on the substrate.

The sprayer used was Nisshin Engineering model DISPA-μR (trademark)sprayer, as shown in FIG. 30. The conductive stage was almost identicalin shape and size with the ITO electrode region on the substrate andthus had a size such that each edge was about 10 mm inside thecorresponding substrate edge, as shown in FIG. 11, and such stage wasdisposed within the sprayer. A connecting terminal for voltageapplication as connected with the voltage application apparatus wasprovided within the spacer and a wiring was led into the sprayer so thatvoltage supply might be made to the substrate.

Micropearl BB-PH (trademark; product of Sekisui Fine Chemical; particlesize: 7.25 μm) were prepared as the spacers.

Then, a voltage of −2.0 kV was applied to all ITO electrodes on thesubstrate by voltage application to the dummy electrode. Whilemaintaining this state, the spacers were passed through a stainlesssteel piping (whereby the spacers were charged negatively (−)) andsprayed onto the substrate using compressed nitrogen gas. That thespacers were negatively charged was confirmed beforehand.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers were located in theinterelectrode gaps, namely at black matrix sites.

Thereafter, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast because of no occurrence of spacers in pixel sites, unlike thecase of spacer spraying by the prior art method of LCD production. Itsdisplay performance was characterized by good display uniformity owingto spacer disposition all over the display area.

EXAMPLE 12

The procedure of Example 11 was followed in the same manner except thatthe black matrix used was a metallic chromium black matrix with a linewidth of 35 μm and the conductive stage used was consisted of twodivided portions respectively corresponding to the two display areas onthe substrate in a manner such that the divided portions each was 5 mminside from each picture frame edge of the black matrix of the relevantdisplay area.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed ininterelectrode gaps, namely at black matrix sites.

Thereafter, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast because of no occurrence of spacers in pixel sites, unlike thecase of spacer spraying by the prior art method of LCD production. Itsdisplay performance was characterized by good display uniformity owingto spacer disposition all over the display area.

EXAMPLE 13

The procedure of Example 11 was followed in the same manner except thatthe conductive stage used was larger by 50 mm than the substrate.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed ininterelectrode gaps, namely at black matrix sites but that almost nospacers had been disposed over about 30 mm on the periphery of thedisplay area.

Thereafter, this substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display performance in the central portion of thedisplay area. In the peripheral portions of the display area, however,the cell thickness was decreased because of absence of spacers, hencedisplay unevenness was observed.

EXAMPLE 14

The procedure of Example 12 was followed in the same manner except thatthe conductive stage used had a size of 40%, 30% or 20% of the displayarea.

Each substrate having the spacers disposed thereon was observed under alight microscope and then used to complete a liquid crystal displaydevice by the conventional process.

When the conductive stage had a size of 40% of the display area, thespacers were disposed in interelectrode gaps, namely at black matrixsites, like in Example 12, and the liquid crystal display devicecompleted showed high contrast owing to the absence of spacers at pixelsites and was characterized by good display uniformity owing to thedisposition of spacers all over the display area.

When the conductive stage had a size of 30% of the display area, somespacers had been disposed at pixel sites as well. With the liquidcrystal display device completed, however, the contrast was littleinfluence by the small number of spacers disposed at pixel sites, andthe device showed high contrast. When the conductive stage had a size of20% of the display area, the spacers were disposed randomly on thedisplay area and the liquid crystal display device completed showed noimprovement in contrast.

EXAMPLE 15

A common electrode substrate for STN type LCD production (glasssubstrate provided with pattern-forming linear transparent electrodes, ametallic chromium black matrix and color filters; aperture size of eachof RGB pixels=80×280 μm, metallic chromium black matrix line width=35μm, acrylic resin overcoat layer=3.0 μm, ITO electrode width=290 μm,interelectrode distance=25 μm, glass thickness=0.7 mm) was prepared asthe substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment. Then, the substrate was washedby showering with pure water and then drained with an air knife.

The ITO electrodes were formed as shown in FIG. 5, so that a voltagemight be applied to all linear transparent electrodes by applying thevoltage to a site outside the display area. However, cutting theconductor portions after spacer spraying gave a common electrodesubstrate not essentially differing from the ordinary one.

The sprayer used was a dry method sprayer produced by NisshinEngineering Co., as shown in FIG. 31. A connecting terminal for voltageapplication as connected with a voltage application apparatus wasprovided in the sprayer and a wire conductor was passed into the sprayerso that a voltage might be supplied to the substrate.

Micropearl BBP (trademark; product of Sekisui Fine Chemical; particlesize: 7.25 μm) were prepared as the spacers.

Then, as the heating/drying step prior to spacer spraying, the colorfilter substrate prepared in the above manner was dried by heating in anoven at 90° C. for 30 minutes for removing moisture. After the dryingstep, the substrate was disposed on an earthed conductive stainlesssteel stage in close contact therewith and, after confirming that thesubstrate showed no warp, the terminal of a direct current power sourcewas connected with the ITO electrodes at sites outside the display area.A voltage of +2.00 kV was then applied, followed by feeding spacersthrough a stainless steel pipeline (whereby spacers were chargedpositively (+)) and spraying them onto the substrate under compressednitrogen. That the spacers were charged negatively on that occasion wasconfirmed beforehand.

The working environment in spacer spraying was at room temperature (23°C.) and a relative humidity of 70%. When a voltage of 1 kV was appliedto the transparent electrodes on the above substrate after heating, thecurrent flowing between the transparent electrodes and the stage wasfound to be on the order of 10-12 A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly ingaps between the respective neighboring ITO electrodes. Thus, no spacerwas found within any display pixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 16

The procedure of Example 15 was followed in the same manner except thatthe step of heating/drying the substrate prior to spacer spraying wasomitted. The current flowing between the transparent electrodes and thestage upon application of a voltage of 1 kV to the transparentelectrodes on the substrate was checked and found to be in the order of10⁻⁵ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed not only inITO electrode gaps but also abundantly on ITO electrodes, namely atdisplay pixels as well.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD was inferiorin contrast to the LCD of Example 15 as a result of the influence ofspacer-due light leakage.

EXAMPLE 17

The procedure of Example 15 was followed in the same manner except thatthe substrate was heated at a temperature of 40° C. for 30 minutes. Thecurrent flowing between the transparent electrodes and the stage uponapplication of a voltage of 1 kV to the transparent electrodes on thesubstrate was checked and found to be in the order of 10⁻⁵ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed not only inITO electrode gaps but also on ITO electrodes, namely at display pixelsites.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD was inferiorin contrast to the LCD of Example 15 as a result of the influence ofspacer-due light leakage.

EXAMPLE 18

The procedure of Example 15 was followed in the same manner except thatthe procedure mentioned below was performed in lieu of the step ofheating/drying substrates prior to spacer spraying.

A hot plate was provided in the spray chamber, and a thin aluminum sheetwas further disposed thereon in close contact with the top of the hotplate. The aluminum sheet was earthed, the hot plate was heated, and thealuminum surface was maintained at 150° C. Then, the substrate wasdisposed in close contact with the aluminum sheet, a voltage of +2.00 kVwas applied to the transparent electrode portions and, 3 minutes later,spacer spraying was carried out in the same manner as in Example 15. Thecurrent flowing between the transparent electrodes and the stage uponapplication of a voltage of 1 kV to the transparent electrodes on thesubstrate was checked and found to be about 10⁻¹¹ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 19

The procedure of Example 15 was followed in the same manner except thatdry nitrogen gas at a gas temperature of 45° C. was blown onto thesubstrate from above and from below in lieu of the step ofheating/drying substrates prior to spacer spraying. The current flowingbetween the transparent electrodes and the stage upon application of avoltage of 1 kV to the transparent electrodes on the substrate waschecked and found to be about 10⁻¹¹ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 20

The procedure of Example 15 was followed in the same manner except thatthe substrate was dipped in acetone and then the acetone was removedfrom the substrate by means of an air knife in lieu of the step ofheating/drying substrates prior to spacer spraying. The current flowingbetween the transparent electrodes and the stage upon application of avoltage of 1 kV to the transparent electrodes on the substrate waschecked and found to be about 10⁻⁷ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 21

The procedure of Example 15 was followed in the same manner except thatthe substrate was placed in a vacuum drier and allowed to stand undervacuum (1 Pa) for 5 hours and then the voltage application to the lineartransparent electrodes and spacer spraying were immediately carried outin lieu of the step of heating/drying substrates prior to spacerspraying. The current flowing between the transparent electrodes and thestage upon application of a voltage of 1 kV to the transparentelectrodes on the substrate was checked and found to be about 10⁻¹¹ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 22

The procedure of Example 15 was followed in the same manner except thatthe environment for storing substrate and the working environment forspacer spraying were both controlled at room temperature (23° C.) and arelative humidity of 40% and the step of heating/drying substrates priorto spacer spraying was omitted. The current flowing between thetransparent electrodes and the stage upon application of a voltage of 1kV to the transparent electrodes on the substrate was checked and foundto be in the order of 10⁻⁷ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 23

The procedure of Example 15 was followed in the same manner except thatthe environment for storing substrate and the working environment forspacer spraying were both controlled at room temperature (23° C.) and arelative humidity of 85% and the step of heating/drying substrates priorto spacer spraying was omitted. The current flowing between thetransparent electrodes and the stage upon application of a voltage of 1kV to the transparent electrodes on the substrate was checked and foundto be in the order of 10⁻⁵ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed not only inITO electrode gaps but also abundantly on ITO electrodes, namely atdisplay pixel sites as well.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD was inferiorin contrast to the LCD of Example 15 as a result of the influence ofspacer-due light leakage.

EXAMPLE 24

The substrate was stored beforehand in an environment maintained at roomtemperature (23° C.) and a relative humidity of 20% and thereafter theprocedure of Example 15 was immediately followed. The step ofheating/drying substrates prior to spacer spraying was omitted and theworking environment for spacer spraying was controlled at roomtemperature (23° C.) and a relative humidity of 50%. The current flowingbetween the transparent electrodes and the stage upon application of avoltage of 1 kV to the transparent electrodes on the substrate waschecked and found to be in the order of 10⁻⁸ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed linearly inthe ITO electrode gaps. Thus, no spacer was found within any displaypixel site.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD showed highcontrast and good display characteristics owing to the absence ofspacer-due light leakage.

EXAMPLE 25

The substrate was stored beforehand in an environment maintained at roomtemperature (8° C.) and a relative humidity of 10% and thereafter theprocedure of Example 15 was immediately followed. The step ofheating/drying substrates prior to spacer spraying was omitted and theworking environment for spacer spraying was controlled at roomtemperature (23° C.) and a relative humidity of 50%. The current flowingbetween the transparent electrodes and the stage upon application of avoltage of 1 kV to the transparent electrodes on the substrate waschecked and found to be in the order of 10⁻⁵ A.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that the spacers had been disposed not only inITO electrode gaps but also abundantly on ITO electrodes, namely atdisplay pixel sites as well.

Thereafter, the substrate was used to complete a liquid crystal displaydevice by the conventional process. The thus-completed LCD was inferiorin contrast to the LCD of Example 15 as a result of the influence ofspacer-due light leakage.

EXAMPLE 26

A common electrode substrate for STN type LCD production (glasssubstrate provided with pattern-forming linear transparent electrodes, ametallic chromium black matrix and color filters; aperture size of eachof RGB pixels=80×280 μm, metallic chromium black matrix line width=25μm, acrylic resin overcoat layer=3.0 μm, ITO electrode width=290 μm,interelectrode distance=15 μm, glass thickness=0.7 mm) was prepared asthe substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

All transparent electrodes (ITO electrodes, stripe electrodes) on thesubstrate were connected within the dummy electrode region to a voltageapplication apparatus so that a direct current voltage might be appliedto all ITO electrodes on the substrate. The voltage applicationapparatus could arbitrarily be adjusted with respect to voltage valueand voltage polarity.

The sprayer used was Nisshin Engineering's DISPA-μR (trademark, drymethod sprayer). The substrate was disposed in close contact with anearthed stainless steel conductive stage. A terminal of the voltageapplication apparatus (direct current power source) for voltageapplication was provided within the spacer and a wiring was led into thesprayer and connected with the dummy electrode on the substrate so thatvoltage supply might be made to all ITO electrodes on the substrate.

Micropearl BB-PH (trademark; product of Sekisui Fine Chemical; particlesize: 7.25 μm) were prepared as the spacers.

Then, a voltage of −2.3 kV was applied to all ITO electrodes on thesubstrate for 1 minute.

Thereafter, the terminal of the voltage application apparatus wasdisconnected, and the spacers were passed through a stainless steelpiping (whereby the spacers were charged negatively (−)) and sprayedonto the substrate by means of compressed air. That the spacers werenegatively charged was confirmed beforehand.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that almost all the spacers had been disposedin the interelectrode gaps, namely at black matrix sites.

EXMPLE 27

In Example 26, an aluminum foil was brought into close contact with thewhole reverse side of the substrate, the terminal of the voltageapplication apparatus was connected with the dummy electrode on thesubstrate on an earthed stainless steel plate, and a voltage of −2.5 kVwas applied to all ITO electrodes for 1 minute.

Thereafter, the terminal of the voltage application apparatus wasdisconnected, the substrate and the aluminum foil, in close contact witheach other, were transferred onto the earthed stainless steel stage inthe spray chamber, and spacer spraying was carried out in the samemanner as in Example 26.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that almost all the spacers had been disposedin the interelectrode gaps, namely at black matrix sites.

EXAMPLE 28

In Example 26, an aluminum foil was brought into close contact with thewhole reverse side of the substrate, the terminal of the voltageapplication apparatus was connected with the dummy electrode on thesubstrate on an earthed stainless steel plate, and a voltage of −2.5 kVwas applied to all ITO electrodes for 1 minute.

Thereafter, the terminal of the voltage application apparatus wasdisconnected, the substrate and the aluminum foil, in close contact witheach other, were transferred onto an insulating table (made of a vinylchloride resin) in the spray chamber, and spacer spraying was carriedout in the same manner as in Example 26.

Observation of the substrate having the spacers disposed thereon under alight microscope revealed that almost all the spacers had been disposedin the interelectrode gaps, namely at black matrix sites.

EXAMPLE 29

A common electrode substrate for STN type LCD production (glasssubstrate provided with pattern-forming linear transparent electrodes, ametallic chromium black matrix and color filters; aperture size of eachof RGB pixels=80×280 μm, metallic chromium black matrix line width=25μm, acrylic resin overcoat layer=3.0 μm, ITO electrode width=290 μm,interelectride distance=15 μm, glass thickness=0.7 mm) was prepared asthe substrate.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

All transparent electrodes (ITO electrodes, stripe electrodes) on thesubstrate were connected within the dummy electrode region to a voltageapplication apparatus so that a direct current voltage might be appliedto all ITO electrodes on the substrate. The voltage applicationapparatus could arbitrarily be adjusted with respect to voltage valueand voltage polarity.

The sprayer used was Nisshin Engineering's DISPA-μR (trademark, drymethod sprayer). The substrate was disposed in close contact with anearthed stainless steel conductive stage. A terminal of the voltageapplication apparatus (direct current power source) for voltageapplication was provided within the spacer and a wiring was led into thesprayer and connected with-the dummy electrode on the substrate so thatvoltage supply might be made to all ITO electrodes on the substrate.

Micropearl BB-PH (trademark; product of Sekisui Fine Chemical; particlesize: 7.25 μm) were prepared as the spacers.

Then, a voltage of −2.0 kV was applied to all ITO electrodes on thesubstrate.

Immediately after voltage application (the duration of voltageapplication being zero) or after 1 second, 3 seconds, 5 seconds, 10seconds or 60 seconds of voltage application, spacers were passedthrough a stainless steel pipeline (whereby the spacers were chargednegatively (−)) and sprayed onto the substrate by means of compressedair. That the spacers were negatively charged was confirmed beforehand.During spacer spraying, the voltage of −2.0 kV was continuously appliedto all ITO electrodes.

Each substrate having the spacers disposed thereon was observed under alight microscope and the state of spacer disposition was evaluated interms of disposition percentage, as follows.

[Disposition percentage (%)]=[number of spacers disposed at black matrixsites per certain number of pixels]/[total number of spacers per thecertain number of pixels]

The results thus obtained are shown in Table 1.

TABLE 1 Duration of voltage application before 0 1 3 5 10 60 spraying(seconds) Disposition percentage (%) 92 94 95 98 >99 >99

EXAMPLE 30

A color filter substrate (glass substrate provided with pattern-forminglinear transparent electrodes, a metallic chromium black matrix and apigment dispersion type color filter layer formed thereon; aperture sizeof each of RGB pixels=80×280 μm, metallic chromium black matrix linewidth=35 μm, pigment dispersion type color filter layer thickness=about1.5 μm, acrylic resin overcoat layer=3.0 μm, glass thickness=0.7 mm) wasprepared as the first substrate.

Then, rectangular etched areas, 25 μm×100 μm in size, were formed overand within the expanse of the corresponding black matrix areas formedcentrally in the horizontal direction, as shown in FIG. 23.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to subbing treatment.

The transparent electrodes were connected with a voltage applicationapparatus at sites outside the display area on the color filtersubstrate and, further, the transparent electrode layer and overcoatlayer were partly scraped off to expose part of the chromium blackmatrix and the black matrix portions were also connected with anothervoltage application apparatus so that a direct current voltage might beapplied thereto. The two voltage application apparatus could arbitrarilybe adjusted with respect to voltage value and voltage polarity.

The sprayer used was a Nisshin Engineering dry sprayer, as shown in FIG.32. The substrate was disposed on an earthed stainless steel conductivestage in close contact with the same. Terminals for voltage applicationas connected with the respective voltage application apparatus wereprovided within the sprayer and wirings were led into the sprayer sothat voltage supply to the substrate might be made.

Micropearl SP (trademark; product of Sekisui Fine Chemical; particlesize: 5.25 μm) were prepared as the spacers.

Then, a voltage of −1.5 kV was applied to the transparent electrodes onthe substrate, and a voltage of −1.48 kV to the black matrix portions(transparent electrodes: relative −, black matrix portions: relative +).While maintaining this state, spacers were passed through a stainlesssteel pipeline (whereby the spacers were charged negatively) and sprayedonto the substrate by means of compressed air. That the spacers arecharged negatively was confirmed beforehand.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed inthe etched areas alone, as shown in FIG. 33.

Thereafter, the substrate was used to complete a TFT type liquid crystaldisplay device by the conventional process. Upon screen observation, thethus-completed TFT type LCD showed high contrast owing to the absence ofspacers in the display area.

EXAMPLE 31

Using the same substrate as used in Example 30, a voltage of −2.0 kV wasapplied from a voltage application apparatus to the transparentelectrodes but the terminal of the voltage application apparatus was notconnected to the black matrix portions. Otherwise, the procedure ofExample 30 was followed.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed inthe etched areas alone.

EXAMPLE 32

The procedure of Example 31 was followed in the same manner except thatan antistatic mat having a resistance value of not more than 10⁷ Ωcm wasdisposed on the stainless steel conductive stage in the spacer sprayerin close contact with the stage and the first substrate was disposedthereon in close contact.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed inthe etched areas alone.

EXAMPLE 33

The procedure of Example 30 was followed in the same manner except thatan antistatic mat having a resistance value of not more than 10⁷ Ωcm wasdisposed on the stainless steel conductive stage in the spacer sprayerin close contact with the stage and the first substrate was disposedthereon in close contact.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed inthe etched areas alone.

Comparative Example 3

An attempt was made to follow the procedure of Example 30 by applying avoltage of −1.5 kV to the transparent electrodes and a voltage of −1.3kV to the black matrix portions. However, short-circuiting occurredbetween the transparent electrodes and the conductive black matrix and,as a result, voltage application could not be carried out.

EXAMPLE 34

A color filter substrate (glass substrate provided with pattern-forminglinear transparent electrodes, a metallic chromium black matrix andcolor filters formed thereon; aperture size of each of RGB pixels=80×280μm, metallic chromium black matrix line width in stripe direction=25 μm,black matrix line width perpendicular to stripe direction=35 μm) wasprepared as the first substrate.

Then, a number of rectangular isolated transparent electrodes, 11 μm×40μm in size, were formed in those sites of the transparent electrodescorresponding to crossings of the black matrix, as shown in FIG. 28, byforming 5-μm-wide etched lines within the range of each 35-μm-wideconductive black matrix line and 7 μm apart from the border thereof.

On this substrate was formed a 0.05-μm-thick polyimide alignment layer,which was subjected to rubbing treatment.

The transparent electrodes were connected with a voltage applicationapparatus at sites outside the display area on the color filtersubstrate so that the transparent electrodes other than the isolatedtransparent electrodes might be connected with the voltage applicationapparatus and a DC voltage might be applied thereto. The voltageapplication apparatus could arbitrarily be adjusted with respect tovoltage value and voltage polarity.

The sprayer used was a Nisshin Engineering dry sprayer, as shown in FIG.34. The substrate was disposed on an earthed stainless steel conductivestage in close contact with the same. A terminal for voltage applicationas connected with the voltage application apparatus was provided withinthe sprayer and a wiring was led into the sprayer so that voltage supplyto the substrate might be made.

Micropearl CB (trademark; product of Sekisui Fine Chemical; particlesize: 5.7 μm) were prepared as the spacers.

Then, a voltage of +1.8 kV was applied to the transparent electrodesother than the isolated transparent electrodes on the substrate. Whilemaintaining this state, spacers were passed through a pipeline (wherebythe spacers were charged positively) and sprayed onto the substrate bymeans of compressed air. That the spacers are positively charged wasconfirmed beforehand.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed, asshown in FIG. 35, only in those sites where there were the isolatedtransparent electrodes formed.

Thereafter, the substrate was used to complete a TFT type liquid crystaldisplay device by the conventional process. Upon screen observation, thethus-completed TFT type LCD showed high contrast owing to the absence ofspacers in the display area.

The spacers adhered to the alignment layer as a result of pressureapplication to a sealing material and heating in the curing process, andtheir translocation or the like was not observed.

EXAMPLE 35

The procedure of Example 34 was followed in the same manner except thatan antistatic mat having a resistance value of not more than 10⁷ Ωcm wasplaced on the stainless steel conductive stage in the spacer sprayer inclose contact with the same, and the first substrate was disposedthereon in close contact.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposedonly in those sites where there were the isolated transparent electrodesformed.

EXAMPLE 36

The procedure of Example 34 was followed in the same manner except thata pigment dispersion type black resist was used in lieu of the chromiumblack matrix and the same pattern as in the case of chromium blackmatrix was formed and that a voltage of +2.0 kV was applied.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposedonly in those sites where there were the isolated transparent electrodesformed.

Comparative Example 4

The procedure of Example 34 was followed in the same manner except thatpins made of a resin comprising a fluoro resin were erected on the stageand the first substrate was disposed thereon to thereby keep the wholefirst substrate apart from the stage for insulation by means of air.

Observation of the first substrate having the spacers disposed thereonunder a light microscope revealed that the spacers had been disposed notonly at black matrix sites but also on the transparent electrodesabundantly and almost randomly.

Industrial Applicability

The method for producing a liquid crystal display device according tothe present invention, which is as mentioned above, is a method ofproducing liquid crystal display devices comprising a substrate havingpattern-forming transparent electrodes formed thereon and makes itpossible to dispose spacers exclusively in electrode-free interelectrodespaces, namely at black matrix sites, to dispose spacers in such a modeall over the display area or to dispose spacers at black matrix siteswith high yield and accuracy, and to reduce the tact time by omittingthe step of voltage application to the transparent electrodes on thesubstrate within the spray chamber.

It is therefore possible to produce liquid crystal display devicesshowing no spacer-due light leakage, showing very high contrast,maintaining a uniform cell thickness and having high quality displayperformance characteristics without showing display unevenness, in astable manner with a reduction in tact time.

Even in the case of TFT type liquid crystal display devices, such liquidcrystal display devices showing very high contrast without showingspacer-due light leakage can be produced.

The liquid crystal display device according to the invention, which isconstituted as mentioned above, shows no spacer-due light leakage, showsvery high contrast, has a uniform cell thickness and has high qualitydisplay performance characteristics without showing display unevenness.

What is claimed is:
 1. A method for producing a liquid crystal displaydevice comprising spraying spacers onto at least one of a firstsubstrate comprising at least pattern-forming transparent electrodes anda second substrate to be disposed opposingly above the first substrateand filling a liquid crystal into the space between both the substrates,wherein, in spraying positively or negatively charged spacers onto thesubstrate, the substrate is disposed in close contact with an earthedconductive stage having a volume resistance of not more than 10¹⁰ Ωcm tothereby improve the precision of selective spacer positioning in a spaceof the transparent electrodes, and a voltage of 1.5 kV to 5 kV havingthe same polarity as the spacer charge polarity is applied to thetransparent electrodes, and the spacers are fixed on the substratesurface by heating.
 2. The method for producing a liquid crystal displaydevice according to claim 1, wherein the substrate has a dummy electrodeand, in applying a voltage to the transparent electrodes, a voltage isapplied to the dummy electrode as well to thereby attain a uniform cellgap.
 3. The method for producing a liquid crystal display deviceaccording to claim 2, wherein the voltage application to the transparentelectrodes is effected by connecting the dummy electrode with thetransparent electrodes and applying a voltage to the dummy electrode. 4.The method for producing a liquid crystal display device according toclaim 2, wherein the voltage applied to the dummy electrode is differentfrom the voltage applied to the transparent electrodes.
 5. A method forproducing a liquid crystal display device comprising spraying spacersonto at least one of a first substrate comprising at leastpattern-forming transparent electrodes, a conductive black matrix and anovercoat layer and a second substrate to be disposed opposingly abovethe first substrate and filling a liquid crystal into the space betweenboth the substrates, wherein, in spraying positively or negativelycharged spacers onto the substrate, a voltage (V1) is applied to theconductive black matrix and a voltage (V2) to the transparentelectrodes, both the voltages V1 and V2 being positive ones andsatisfying the relation V1<V2 when the spacer charge polarity ispositive, or both V1 and V2 being negative voltages and satisfying therelation V1<V2 when the spacer charge polarity is negative, and thepotential difference between V1 and V2 is not more than 100V.
 6. Amethod for producing a liquid crystal display device comprising sprayingspacers onto at least one of a first substrate comprising at leastpattern-forming transparent electrodes, an alignment layer and one ormore display areas and a second substrate to be disposed opposinglyabove the first substrate and filling a liquid crystal into the spacebetween both the substrates, wherein, in spraying positively ornegatively charged spacers onto the substrate, the substrate is disposedin close contact with an earthed conductive stage smaller in size thanthe substrate to thereby allow the peripheral edge portions thereof tobe apart from the conductive stage and a voltage of the same polarity asthe spacer charge polarity is applied to the transparent electrodes onthe substrate to thereby prevent the decrease in the number of spacersdisposed on the periphery of the substrate.
 7. The method for producinga liquid crystal display device according to claim 6, wherein thesubstrate onto which spacers are to be sprayed has a black matrix formedthereon, said black matrix being conductive and said conductive stagecomprising one or more parts each smaller in size as compared with thepicture-frame peripheral edges of the black matrix of each display areaon the substrate.
 8. The method for producing a liquid crystal displaydevice according to claim 6, wherein the area of contact between theconductive stage and the substrate is not less than 30% of the part ofthe display area.
 9. A method for producing a liquid crystal displaydevice comprising spraying spacers onto at least one of a firstsubstrate comprising at least pattern-forming transparent electrodes andan alignment layer and a second substrate to be disposed opposinglyabove the first substrate and filling a liquid crystal into the spacebetween both the substrates, and comprising the step of removingmoisture from the substrate onto which spacers are to be sprayed, thestep of disposing the substrate into close contact with an earthedconductive stage and then spraying spacers while applying a voltage ofthe same polarity as the spacer charge polarity to the transparentelectrodes on the substrate to thereby improve the precision ofselective spacer positioning in a space of the transparent electrodeswherein, upon application of a voltage of 1 kV to the transparentelectrodes on the substrate after completion of the step of removingmoisture, the current flowing between the transparent electrodes on thesubstrate and the conductive stage is not more than 10⁻⁶ A.
 10. Themethod for producing a liquid crystal display device according to claim9, wherein the step of removing moisture is carried out by heating thesubstrate prior to spacer spraying.
 11. The method for producing aliquid crystal display device according to claim 10, wherein the heatingof the substrate is carried out at a temperature of not lower than 50°C.
 12. The method for producing a liquid crystal display deviceaccording to claim 9, wherein the step of removing moisture is carriedout by heating the substrate during spacer spraying.
 13. The method forproducing a liquid crystal display device according to claim 9, whereinthe step of removing moisture is carried out by blowing a dry gas ontothe substrate prior to spacer spraying.
 14. The method for producing aliquid crystal display device according to claim 9, wherein the step ofremoving moisture is carried out by replacing moisture with a solventprior to spacer spraying.
 15. The method for producing a liquid crystaldisplay device according to claim 9, wherein the step of removingmoisture is carried out by allowing the substrate to stand under vacuumor by heating the substrate under vacuum prior to spacer spraying.
 16. Amethod for producing a liquid crystal display device comprising sprayingspacers onto at least one of a first substrate comprising at leastpattern-forming transparent electrodes and an alignment layer and asecond substrate to be disposed opposingly above the first substrate andfilling a liquid crystal into the space between both the substrates, andcomprising the step of disposing the substrate into close contact withan earthed conductive stage and spraying spacers while applying avoltage of the same polarity as the spacer charge polarity to thetransparent electrodes on the substrate, the substrate before and duringspacer spraying showing characteristics such that, when a voltage of 1kV is applied to the transparent electrodes on the substrate, thecurrent flowing between the transparent electrodes on the substrate andthe conductive stage is not more than 10⁻⁶ A to thereby improve theprecision of selective spacer positioning in a space of the transparentelectrodes.
 17. The method for producing a liquid crystal display deviceaccording to claim 16, wherein the step of disposing the substrate intoclose contact with an earthed conductive stage and spraying spacerswhile applying a voltage of the same polarity as the spacer chargepolarity to the transparent electrodes on the substrate is carried outunder conditions controlled so that the temperature is within the roomtemperature range, namely 18° C. to 28° C. and the relative humidityamounts to not more than 50% RH.
 18. The method for producing a liquidcrystal display device according to claim 17, wherein the substrate iskept in an environment where the temperature is within the roomtemperature range, namely 18° C. to 28° C. and the relative humidityamounts to not more than 50% RH.
 19. A method for producing a liquidcrystal display device comprising spraying spacers onto at least one ofa first substrate comprising at least pattern-forming transparentelectrodes and an alignment layer and a second substrate to be disposedopposingly above the first substrate and filling a liquid crystal intothe space between both the substrates, wherein, in spraying positivelyor negatively charged spacers onto the substrate, the substrate isdisposed in close contact with an earthed conductive stage, a voltage ofthe same polarity as the spacer charge polarity is applied to thetransparent electrodes on the substrate, then the terminals of thevoltage application apparatus are disconnected from the transparentelectrodes and spacer spraying is carried out while the electric chargeremains on the substrate.
 20. The method for producing a liquid crystaldisplay device according to claim 19, wherein the earthed conductivestage is a mobile one and, in spraying positively or negatively chargedspacers onto the substrate, the substrate is disposed in close contactwith the conductive stage, then a voltage of the same polarity as thespacer charge polarity is applied to the transparent electrodes on thesubstrate, the terminals of the voltage application apparatus aredisconnected from the transparent electrodes, the conductive stagetogether with the substrate in close contact therewith is transferred toa spacer sprayer, and thereafter, spacer spraying is carried out.
 21. Amethod for producing a liquid crystal display device comprising sprayingspacers onto at least one of a first substrate comprising at leastpattern-forming transparent electrode and an alignment layer and asecond substrate to be disposed opposingly above the first substrate andfilling a liquid crystal into the space between both the substrates,wherein, in spraying positively or negatively charged spacers onto thesubstrate, the substrate is disposed in close contact with an earthedconductive stage, a voltage of the same polarity as the spacer chargepolarity is applied to the transparent electrodes on the substrate whilemaintaining that state of voltage application for a certain period oftime, and then spacer spraying is carried out while maintaining thatstate of voltage application.
 22. The method for producing a liquidcrystal display device according to claim 21, wherein the voltageapplication state is maintained at least for 5 minutes prior to carryingout spacer spraying while maintaining that state of voltage application.23. A method for producing a liquid crystal display device comprisingspraying spacers onto a first substrate comprising at leastpattern-forming transparent electrodes, a conductive black matrix, anovercoat layer and an alignment layer, and filling a liquid crystal intothe space between the first substrate and a second substrate comprisingthin film transistors formed thereon which is to be disposed opposinglyabove the first substrate, wherein the first substrate has transparentelectrode-free etched regions formed within the transparent electrodesover and within the expanse of the corresponding conductive black matrixareas, and, in spraying positively or negatively charged spacers ontothe first substrate, a voltage (V1) is applied to the conductive blackmatrix and a voltage (V2) to the transparent electrodes, both thevoltages V1 and V2 being positive ones and satisfying the relation V1<V2when the spacer charge polarity is positive, or both V1 and V2 beingnegative voltages and satisfying the relation V1>V2 when the spacercharge polarity is negative, and the potential difference between V1 andV2 is not more than 100V.
 24. A method for producing a liquid crystaldisplay device comprising spraying spacers onto a first substratecomprising at least pattern-forming transparent electrodes, a blackmatrix, an overcoat layer and an alignment layer, and filling a liquidcrystal into the space between the first substrate and a secondsubstrate comprising thin film transistors formed thereon which is to bedisposed opposingly above the first substrate wherein the firstsubstrate has transparent electrode-free etched regions formed withinthe transparent electrodes over and within the expanse of thecorresponding conductive black matrix areas, and, in spraying positivelyor negatively charged spacers onto the first substrate, the firstsubstrate is disposed in close contact with an earthed conductive stagehaving a volume resistance of not more than 10¹⁰ Ωcm and a voltage of200 V to 5 kV having the same polarity as the spacer charge polarity isapplied to the transparent electrodes, and the spacers are fixed on thesubstrate surface by heating.
 25. A method for producing a liquidcrystal display device comprising spraying spacers onto a firstsubstrate comprising at least pattern-forming transparent electrodes,and filling a liquid crystal into the space between the first substrateand a second substrate comprising thin film transistors formed thereonwhich is to be disposed opposingly above the first substrate, whereinthe first substrate has isolated, electrically floating, transparentelectrodes not connected with the surrounding transparent electrodes butformed within the transparent electrodes within the expanse of thecorresponding black matrix areas as formed on the first or secondsubstrate, and, in spraying positively or negatively charged spacersonto the first substrate, the first substrate is disposed in closecontact with an earthed conductive stage having a volume resistance ofnot more than 10¹⁰ Ωcm and a voltage of the same polarity as the spacercharge polarity is applied to the transparent electrodes other than theisolated transparent electrodes on the first substrate.
 26. The methodfor producing a liquid crystal display device according to claim 1, 5,9, 16, 19, 21, 23, 24 or
 25. wherein spacers are charged positively ornegatively by being sprayed through a pipeline made of a resin or ametal using a gas as a medium.
 27. The method for producing a liquidcrystal display device according to claim 5, 6, 9, 16, 19, 21, 23, or25. wherein spacers are fixed on the substrate surface by heating.
 28. Aliquid crystal display device produced by the method for producing aliquid crystal display device according to claim 1, 5, 6, 9, 16, 19, 21,23, 24 or 25.